
PROVISIONAL 

MACHINE-GUN FIRING 

MANUAL 



1Q17 




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Book <h ~£. 



PROVISIONAL 

MACHINE-GUN FIRING 
MANUAL 



1917 




)/m\n-7Sl 



WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1917 






«,°?1 V 



Wab Depaktment, 

Document No. 615. 

Office of The Adjutant General. 



D« of D* 
NOV 16 191/ 



£^ 



WAR DEPARTMENT, 

Washington, June 21, 1917. 
The following Provisional Machine Gun Firing Manual, 1917, 
is published for the information and guidance of all concerned. 

[1854484 A. G. O.] 

By order of the Secretary of War: 

TASKER H. BLISS, 

Major General, Acting Chief of Staff. 
Official : 

h. p. McCain, 

The Adjutant General. 

3 



TABLE OF CONTENTS. 



PART I.— GENERAL SCHEME. Par. 

Object of instruction , 1 

Scheme of instruction 2 

Supplementary practice season 5 

PART II.— INDIVIDUAL INSTRUCTION. 

Chapter I. — Nomenclature, use, care, and repair of machine 

guns and accessories 11 

Instruction in the mechanics of the gun 13 

Use of ordnance handbooks and manuals 14 

Chapter II. — Physical training 15 

Chapter III. — Sighting, position,, and aiming drills : 

Sighting and aiming drills 18 

Sighting exercises , 27 

Position exercises 38 

Benet-Mercie rifle 39 

Lewis gun 40 

Vickers gun 42 

Maxim gun 43 

Aiming exercises 45 

Chapter IV. — Use of instruments 52 

Field glasses 53 

Range finders 54 

Mil scale 55 

Sights 56 

Prismatic compass . 57 

Clinometer and handlevel 58 

Chapter V. — The determination of ranges 59 

Estimating distances on the ground by eye 59 

From map 76 

From troops already engaged 77 

Measuring directly on ground-- 78 

By sound _ 79 

By range finders : 80 

Range estimators 81 

Chapter VI. — Recognition and designation of service targets- 82 

Recognition of targets 82 

Target designation 89 

Chapter VII. — Known distance practice 94 

Instruction practice 98 

5 



6 TABLE OF CONTENTS. 

PART II.— INDIVIDUAL INSTRUCTION— Continued. Par. 

Chapter VIII. — Record practice 110 

Chapter IX. — The determination of sight setting 111 

Chapter X. — Instruction field firing 114 

Chapter XI. — Indirect fire 116 

Chapter XII. — Overhead fire 124 

Chapter XIII. — Night firing 129 

Night-firing box 130 

Chapter XIV. — Individual qualification tests 131 

Materiel 132 

Determination of range ;_ 133 

Sight setting and recognition of targets 134 

Individual record known distance firing 135 

Individual field firing test . 136 

PART III.— COMBAT FIRING. 

Chapter I. — Fire problems : 137 

Machine-gun commander's problems 147 

Chapter II. — Drill exercises* * . : 160 

Chapter III. — The conduct of field-firing exercises 171 

Chapter IV. — The critique of field-firing exercises 183 

Chapter V. — Combat practice, record __. 188 

PART IV.— THE THEORY OF FIRE. 

Chapter I. — Ballistic qualities of machine guns 189 

Powers 191. 

Limitations 198 

Chapter II. — Rates and volumes and their relation to effec- 
tiveness 205 

Cyclic rate — 205 

Rate of fire 206 

Volume of fire 208 

Rate of impact 209 

Volume of impact 210 

Distribution factor 211 

Amount of fire 212 

Effectiveness of fire 213 

Chapter III. — Adjustment of fire - 216 

Choice of means 217 

The battle sight — 217 

The use of a single elevation 218 

Ranging fire__: 219 

Combined sights and searching fire_ 225 

Fire for effect 1 230 

PART V.— TARGETS AND RANGES. 

Target for obtaining sight setting of machine guns 240 

Known distance targets 241 

Field targets • 247 



TABLE OF CONTENTS. T 

PART V.— TARGETS AND RANGES— Continued. 

Ranges : Par:. 

Class A range 25$ 

Machine-gun range 267 

Class B range 274. 

Range regulations 275 

PART VI.— MISCELLANEOUS. 

Chapter I. — Records and reports 287 

Chapter II. — Classification, insignia, and extra compensa- 
tion 294 

Insignia 296 

Extra compensation 30O 

PART VII.— COURSES FOR ORGANIZATIONS NOT IN REGU- 
LAR SERVICE 301 

APPENDIX. — Syllabus of combat training. 



LIST OF PLATES. 



Plate 1. Sighting apparatus. 

Plate 2. Normal sight ; peep sight ; fine sight. 

Plate 3. Illustrating focusing on bull's-eye, front sight and rear sight, 

respectively. 
Plate 4. Sighting gauge. 

Plate 5. Benet-Mercie rifle, correct position. 
Plate 6. Benet-Mercie rifle, correct position. 
Plate 7. Benet-Mercie rifle, correct position. 
Plate 8. Benet-Mercie rifle, correct position. 
Plate 9. Benet-Mercie rifle, correct position. 
Plate 10. Benet-Mercie rifle, good position in tree. 
Plate 11. Benet-Mercie rifle, correct position on hillside. 
Plate 12. Benet-Mercie rifle, incorrect position. 
Plate 13. Benet-Mercie rifle, incorrect position. 
Plate 14. Benet-Mercie rifle, incorrect position. 
Plate 15. Benet-Mercie piece canted on hillside. 
Plate 16. Benet-Mercie" rifle, head not in position to see sights. 
Plate 17. Benet-Mercie rifle, incorrect position. 
Plate 18. Lewis gun, showing butt tang, disk on rear sight slide, and 

front sight cover attached. 
Plate 19. Lewis gun, correct position, body in prolongation of barrel. 
Plate 20. Lewis gun, correct position, front view. 
Plate 21. Lewis gun, incorrect position, body at angle. 
Plate 22. Lewis gun, incorrect position, exposure of body and leg. 
Plate 23. Lewis gun, reloading. 
Plate 24. Lewis gun, correct position on hillside. 
Plate 25, Lewis gun, correct firing around corner of building. 
Plate 26. Lewis gun, correct firing over parapet of trench, loader in 

incorrect position, fully exposed. 
Plate 27. Lewis gun, correct firing over parapet, front view. 
Plate 28. Lewis gun, correct firing over parapet, side view. 
Plate 29. Lewis gun, correct firing from position in tree. 
Plate 30. Vickers gun, correct position for firing. 
Plate 31. Vickers gun, correct position for firing from entrenchment. 
Plate 32. Vickers gun, incorrect set up ; top carriage too far to front. 
Plate 33. Vickers gun, correct position for emergency fire to left flank. 
Plate 34. Vickers gun, correct position for firing up very steep slope. 
Plate 35. Vickers gun, correct position for firing on rough ground. 

9 



10 LIST OF PLATES. 

Plate 36. Vickers gun, correct position for firing ; mount in intermediate 

position. 
Plate 37. Vickers gun, correct position for firing, crew in position. 
Plate 38. Vickers gun, correct position for firing, prone. 
Plate 39. Vickers gun, correct position for firing, prone. 
Plate 40. Vickers gun, incorrect set up. 
Plate 41. Maxim gun, corect position, trail in. 
Plate 42. Maxim gun, correct position, trail out. 
Plate 43. Maxim gun, incorrect position, trail in. 
Plate 44. Maxim gun, incorrect position, trail out. 
Plate 45. Numbered aiming points. 
Plate 46. Correct travel of line of aim. 
Plate 47. Incorrect travel of line of aim. 

Plate 48. Travel of line of aim, searching with distribution, diagonal. 
Plate 49. Estimating distance drill, clock designation. 
Plate 50. Suggested exercise in estimating distance drill. 
Plate 51. Shot-group gauges. 
Plate 52. Scale of M. G. ordinates at 1,000 inches from the muzzle of 

gun. 
Plate 53. Ground map with compass. 
Plate 54. Ground map without compass. 
Plate 55. Ground map without compass. 
Plate 56. Finding angle of site. 
Plate 57. Overhead fire. 
Plate 58. Night firing box. 
Plate 59. Aiming tripod. 

Plate 60. Illustrating correct and incorrect target designation. 
Plate 61. Battle sight sheaf of automatic machine rifle, showing ranges 

at which various targets come within the effective (75 per 

cent) portion of the beaten zone. 
Plate 62. Sight correction as result of ranging fire. 
Plate 63. Sight correction as result of ranging fire. 
Plate 64. Machine-gun targets A, B, and C. 
Plate 65. Machine-gun target D. 
Plate 66. Targets B, E, F, G, and H. 
Plate 67. Targets I and K. 
Plate 68. Diagram showing area and dimensions of known distance 

range. 
Plate 69. Plan of a known distance machine-gun range. 
Plate 70. Plan of class B range. 



PROVISIONAL MACHINE-GUN FIRING MANUAL 



DEFINITIONS. 

Aiming device: A device to be attached to the machine gun 
whereby the soldier's aim can be verified. 

Anemometer: An instrument for measuring the velocity of the 
wind. 

Automatic fire : Continued pressure on the trigger results in 
continuous or automatic fire to the limit of the belt, magazine, 
or strip. To have automatic fire with the Benet gun the cock- 
ing handle must first be set at "A." 

Battle sight: The position of the rear sight in which the leaf 
is laid down. 

Beaten zone: The intersection of the cone of dispersion witli 
the surface on which the objective of the fire stands, or the 
space on the ground in which the bullets strike, in a series 
of shots fired by a body of soldiers with the same aiming 
point and the same rear-sight setting. 

Bore : The cylindrical cavity in the machine-gun barrel. 

Butt: The embankment or other means used to stop bullets in 
rear of the target. The plural " butts " is used to designate 
collectively the parapet, the pit, and back stop of a group 
of targets. 

Caliber: The interior diameter of the small-arms barrel, meas- 
ured between the lands. 

Classification: The arranging of the individuals of an organi- 
zation in groups or classes according to the degree of skill 
displayed in record practice on the range with the machine 
gun. 

11 



12 DEFINITIONS. 

Combat practice: The prescribed tiring at targets which simu- 
late the appearance of an enemy under conditions approach- 
ing those found in war, and the application of this class of 
fire to tactical exercises. 

Combined sights: Are used for the same purpose as searching 
fire, i. e., to secure distribution in the direction of depth. 
For this fire two or more guns must be employed, and such 
differences made in the elevation of the guns or each pair of 
guns that their beaten zones will overlap and a greater total 
depth of beaten zone be thus secured. 

Cone of dispersion: A term applied to the figure formed in 
space by the trajectories considered together of a series of. 
shots fired by a body of troops at a common objective and 
with the same rear-sight setting. 

Danger space : The sum of the distances in the path of the bul- 
let in which an object of given height will be struck. At long 
ranges the danger spaces at the farther end of the range 
alone is considered. 

Defilade: An obstacle either natural or artificial of sufficient 
thickness to intercept projectiles and afford shelter from fire 
delivered from a given point, 

Distributed tire: Is that in which the fire is distributed along 
a line, a number of different aiming points being used. These 
points must be selected close together to insure the target 
being covered with fire. 

Drift: The lateral deviation of the bullet caused by the resis- 
tance of the air and the rotation of the bullet on its longer 
axis. 

Estimating distance: Judgment by the eye of the distance of 
an object from the observer. Distance may also be judged 
by sound. 

Expert rifleman, machine gun: The highest grade or classi- 
fication for skill displayed in the qualification test. 



DEFINITIONS. . 13 

Fire for effect: Has for its object the infliction of losses upon 
the enemy. 

Fire control: Or conduct of fire, is the exercise by a com- 
mander, over his unit or units, of that power which enables 
him to regulate the fire in obedience to his will. It pertains 
especially to the technicalities immediately involved in de- 
livery of fire. 

Fire direction: Or employment of fire, is a general term em- 
bracing the various steps, including tactical disposition, which 
enable the commander of one or more fire units to bring an 
effective fire to bear upon the desired target at the proper 
time. It pertains especially to preparation of fire. 

Fire discipline: Is that condition of the personnel of a fire 
unit, resulting from training and practice, which enables the 
commander to obtain an orderly and efficient delivery of fire. 

Fixed lire: Is that class of fire in which the gun is directed 
and fire delivered at a small target, or at a single aiming 
point on a large target. 

Insignia: Badges or distinguishing marks issued for expert- 
ness with the machine gun. 

Instruction practice : The prescribed firing on the range which 
precedes record practice and which is devoted to the instruc- 
tion of the soldier. 

Line of aim: The imaginary right line joining the middle 
point of the horizontal line of the open sight, or the center 
of the peep sight, and the point of aim, 

Marksman, machine gun: The grade of machine-gun man just 
below that of sharpshooter. 

Mil : Is that angle whose tangent is 0.001. Is used for the 
computations required in the control of fire. Its value in 
conventional angular measure is 3' 26.2". 

Mirage: A word used to designate the heat waves observed on 
the target range on warm days. The waves indicate the 
direction in which the air is moving. 



14 DEFINITIONS. 

Mil scale: In an instrument for the measurement of angles. 
Parapet: An elevation of earth or other material thrown up 

in front of the targets to protect the markers. 
Prone: Lying flat on the belly. The only position with the 

body extended on the ground authorized in known distance 

firing. 
Range: Any tract of land over which firing with small arms is 

conducted. This term is also used to signify the distance of 

the objective from the firer. 
Range officer: A commissioned officer charged with the care, 

police, etc., of a target range and its accessories. 
Ranging fire: Has for its object the determination or verifica- 
tion of the firing data when no range-finding instrument is 

available. 
Richochet shots: Bullets which rebound after striking the 

ground or any other obstacle and continue their flight are said 

to ricochet. 

Searching fire: Is that in which the fire of the gun is dis- 
tributed in the direction of depth. 

Sharpshooter, machine gun: A grade of machine-gun man just 
below that of expert rifleman, machine gun. 

String or hursts: A certain number of shots fired in strings 
(or bursts) of 3, 5, 10, etc., with a slight pause between each 
string. 

Telescopic sight: A telescope or other magnifying device at- 
tached to the machine gun for getting, while aiming, a better 
definition of a distant objective, provision being made for 
adjustments in elevation and for windage. 

Trajectory: The path described by a bullet in the air moving 
under the combined influences of the force of propulsion, the 
force of gravity, and the resistance of the air. 



DEFINITIONS. 15 

Twist : The spiral formed by the grooves in the barrel of a 
rifled piece. In the barrel of the machine gnns this twist is 
uniform, one turn in 10 inches. 

Unqualified: Those who in the last practice season failed to 
qualify as a marksman, machine gun, or better, and those 
who for any reason did not fire the course and are not other- 
wise classified. 

Windage: The influence of the wind in deflecting the bullet 
from the point at which it is aimed. 

"Wind gauge: A graduated attachment on the rear sight of the 
gun by which allowance may be made in aiming for the effect 
of the wind upon the bullet and for drift. 



PART I. 



GENERAL SCHEME. 

1. Object of Instruction. — The machine gun is a weapon of 
remarkable powers and limitations. The ultimate purpose of 
machine-gun instruction is to insure, by means of a thoroughly 
trained personnel, a minimizing of the gun's limitations and a 
maximum effective utilization of its fire power on the field of 
battle. 

, A satisfactory course of instruction should therefore be pro- 
gressive, treating first of the training of the individual and then 
of the organization as a whole. 

2. Scheme of Instruction. — The course is arranged herein 
as follows : 

(1) INDIVIDUAL. 

(a) Nomenclature, use, care and repair of guns, and acces- 
sories. 

(b) Physical training. 

(c) Sighting, position, and aiming exercises. 

(d) Use of instruments. 

(e) The determination of ranges. 

(/) Recognition and designation of targets. 
(g) Known distance firing, instruction practice. 
(h) Known distance firing, record practice. 
(i) Determination of sight setting. 
(j) Field firing, instruction practice. 
(k) Indirect fire. 
(I) Overhead fire. 
(m) Night firing. 
106191°— 17 2 17 



18 MACHINE-GUN FIRING MANUAL. 

(n) Qualification tests: 

A. Materiel. 

B. Determination of ranges. 

C. Sight setting and recognition of targets. 

D. Record of known distance practice (taken from 

company records). 

E. Field firing. 

(2) COLLECTIVE. 

(a) Combat firing, instruction practice. 
(&) Combat firing, record practice. 

3. The Course in Pistol Firing Includes the Following 
(see S. A. F. M.) : 

(a) Nomenclature and care of the pistol, general facts and 
principles. 

(6) Position and aiming drills and rapid-fire drills, dis- 
mounted. 

(c) Individual firing, instruction practice. 

(d) Individual firing, record practice. 

4. Period of Preliminary Instruction. — Instruction in the 
nomenclature, use, care and repair of guns, and accessories is 
given each man as soon as possible after he joins the organiza- 
tion. The portion of the year which immediately precedes the 
instruction of the soldier on the target range should be utilized 
in physical-training drills, sighting, position and aiming drills, 
use of instruments, determination of ranges, recognition and 
designation of targets and the theoretical principles of indirect 
fire, overhead fire, night firing, adjustment of fire, and fire for 
effect. 

While it is essential that the gun crews, and especially the men 
who actually handle the guns, be trained to the highest degree 
of expertness in. the firing of the guns, it must be emphasized 
that in battle the guns must never stop firing through lack of a 
trained personnel, hence every member of a machine-gun organi- 



MACHINE-GUN FIRING MANUAL. 19 

zation must be given an adequate course of instruction. There- 
fore, every officer and enlisted man in the organization is re- 
quired each year to go through the course of preliminary 
training and, with the exception of the cooks, the sick, and 
those absent under proper authority, all officers and enlisted 
men who join prior to known distance firing will take part in 
the individual firing to include the known distance firing in the 
qualification test. The cooks are authorized but not required to 
fire. 

5. Stjpplementaky Pbactice Season. — A supplementary 
course of instruction is prescribed for the benefit of recruits 
This practice is for the purpose of preventing an accumulation 
of recruits totally uninstructed. 

0. Discretion Allowed Instructors. — Standards of pro- 
ficiency being set for the individual and the organization and 
the purposes of target practice being understood, it is expected 
that as far as practicable instructors will be given some latitude 
in methods to* suit peculiarities of individuals and special condi- 
tions. Accordingly, while the methods laid down for the pre- 
liminary work and instruction courses are given in some detail, 
these need not necessarily be followed implicitly when departures 
therefrom appear to be justifiable or advantageous. The educa- 
tion and training of the soldier is a long and tedious process, 
consequently improvements in methods should be constantly 
sought by the instructor with a view to raising the standards 
of instruction, decreasing its cost, and shortening the time re- 
quired for training. Reports should be made of new and suc- 
cessfully applied methods. 

7. Duties of Company and Troop Officers. — The company 
or troop commander is responsible for the training of the indi- 
viduals of his organization. He is responsible that his organi- 
zation attains a suitable standard of proficiency. He will be 
assisted by his lieutenants, noncommissioned officers, and such 
men of the organization as are experts in one or more phases of 
the work. These assistants must have the theoretical and 



20 MACHINE-GUN FIRING MANUAL. 

practical instruction necessary to fit them to be coaches and 
instructors. 

8. Duties of the Regimental Commander. — The regimental 
commander is the supervisor and inspector of the firing instruc- 
tion of the machine-gun organization of his regiment. Through 
observation and supervision he assures himself that the organi- 
zation is receiving proper instruction in accordance with the 
spirit of these regulations. He supervises the combat firing 
exercises of the machine-gun organization and endeavors to de- 
velop to the fullest extent the educational value of these exer- 
cises. The actual conduct of the exercises may be turned over 
by the regimental commander to a suitable officer, but in all 
such exercises in which the machine-gun organization partici- 
pates as a whole he will be present whenever possible. 

At the end of the target season he will submit, with the report 
of combat firing (pars. 287-293), a brief report upon the state 
of the instruction and training of the machine-gun organization 
with reference to its fire efficiency. 

9. Duties of the Post, Camp, oe Cantonment Commander. — 
The post, camp, or cantonment commander will exercise a 
general supervision of the machine-gun practice of troops at his 
post and direct supervision over the machine-gun practice of 
troops pertaining to the tactical unit to which he belongs. 
When troops of different brigades are serving at the same post 
lie will see that the approved programs with reference to 
machine-gun practice prescribed in accordance with instruc- 
tion orders of the War Department are faithfully complied 
w^th. 

He will designate the months of the year most suitable for 
machine-gun practice, including the supplementary practice 
season, for his command, and when combat-firing facilities do 
not exist on the reservation should use every effort to procure 
suitable grounds in the vicinity so that the advantage of this 
training may not be lost. 



MACHINE-GUN FIRING MANUAL. 21 

10. Duties of the Department Commander. — The depart- 
ment commander will supervise the machine-gun training of 
the troops in his department, and will make every effort 
to have complete facilities for this instruction at every 
post. He will satisfy himself that the purposes of instruction 
in firing are fully understood and carried out, and to this end 
he will make the necessary examination of the firing records 
and order such test firings at the time of his annual inspection 
as he may deem advisable and of which the ammunition avail- 
able will admit. 



PART II. 



INDIVIDUAL INSTRUCTION. 



CHAPTER I. 

NOMENCLATURE, USE, CARE, AND REPAIR OF MACHINE GUNS 
AND ACCESSORIES. 

11. Definition. — An automatic machine gun may be broadly 
defined as a device for firing small-arms ammunition at a high 
rate of speed, the operations of loading, firing, and ejection be- 
ing performed by the gun itself. 

It is desirable, however, to distinguish between the two types 
of weapons which conform to this general definition. A machine 
gun is a water-cooled gun, mounted on a tripod or other mount 
weighing approximately as much as the gun, and capable of a 
continuous fire limited only by the ammunition supply. The 
Maxim and Tickers are such guns. An automatic rifle is an 
air-cooled gun not capable of continuous fire both on account 
of the manner of loading and on account of the inability of the 
air-cooling system 'to take care of the heating caused by continu- 
ous fire and intended to be carried and fired approximately like 
an infantry rifle. The Lewis and Benet-Mercie are of the auto- 
matic-rifle type. 

For convenience, the machine gun proper is designated herein 
as the heavy gun and the automatic rifle as the light gun, while 
the term " machine gun " includes both types. 
22 



MACHINE-GUN FIRING MANUAL. 23 

12. Machine guns are again divided into two classes, depend- 
ing upon the source of power used for performing the mechani- 
cal operations involved. These are (c) recoil-operated guns,. 
which are operated by the movement of the barrel to the rear 
as the bullet leaves the muzzle, and (&) gas-operated guns, 
which utilize the pressure of the powder gas on a piston for 
motive power. 

These weapons are nothing more than highly specialized gas 
engines with all the complications of this type of machine. It 
is therefore essential that there be a thorough familiarity with 
the operation of the gun as a piece of machinery before any 
attempt is made to utilize its fire effect. 

13. Instruction in the Mechanics of the Gun. — The sol- 
dier as soon as practicable after joining the organization will 
be given thorough training in the nomenclature, functions of 
the parts, and operation of the gun. The instructor will simu- 
late jams and other gun troubles and will require the soldier 
to explain and correct them. Similar instruction will be given 
in the use and care of the accessories, such as the mount, load- 
ing machine, etc., and in the replacing of damaged and broken 
parts of the gun and accessories, using the spnre parts furnished. 
Spare parts will, however, be habitually retained in their con- 
tainers and not used in firing, except when necessary to replace 
damaged parts in the gun. In this way the spare parts on hand 
will always be new and serviceable. The instruction under fhis 
paragraph will be completed before the soldier begins individual 
firing on the range. 

14. Use of Ordnance Handbooks and Manuals. — The ord- 
nance publications on the nomenclature, use, care, and repair 
of the particular gun and equipment with which the organiza- 
tion is armed will be used as the text in the instruction to be 
given under the preceding paragraph. 



24 MACHINE-GUN FIRING MANUAL. 

CHAPTER II. 
PHYSICAL TRAINING. 



_ 



15. Object. — Physical training is for the purpose of develop- 
ing the soldier physically, especially the lungs and the muscles 
of the arms, hands, shoulders, chest, back, neck, and eye. 

The muscles used in the act of firing a machine gun are not 
those in daily use in the ordinary walks of life. It is necessary 
therefore to train them in such manner as to assure their prompt 
and accurate obedience to the will. 

The various calisthenic exercises in general use throughout 
the service, and outlined in the Manual of Physical Training, 
when carefully followed, give excellent results. 

16. ~ In calisthenic exercises it is advantageous to apply the 
principle of muscular opposition. For example, if the exer- 
cise is to bend the arm at the elbow, oppose that movement with 
the muscles which straighten the arm ; if bending the body to the 
right, oppose the movement with the muscles which bend the 
body to the left ; if bending the head to the front, oppose it 
■with the muscles which ( move the head to the rear, etc. By 
this procedure, all the muscles are made to do a greater amount 
•Of work and hence development is quicker. 

Muscular training is essential in order that prolonged firing 
*nay not result in movements becoming slow and inaccurate 
^because of fatigue. 



CHAPTER III. 

SIGHTING, POSITION, AND AIMING DRILLS. 

17. Object. — These exercises are designed with a view to 
giving the soldier practice; in assuming the firing position 
quickly and correctly ; in sighting quickly and with pre- 



MACHINE-GUN FIRING MANUAL. 25 

cision ; in the use of the elevating and traversing mechanism 
thus insuring its movement in the proper direction without 
hesitation or error ; in reloading to the point where this opera- 
tion becomes almost automatic, and in making such changes 
in the point of aim as would be required in distributing fire over 
targets of various shapes and sizes. 

A thorough course in preliminary exercises given the soldier 
prior to his known distance practice, should give a knowledge 
of what to do and the manual dexterity requisite to the accom- 
plishment of his task. 

SIGHTING AND AIMING DRILLS. 

18. Value. — The value of sighting and aiming drills can not 
be too strongly emphasized. 

19. To Whom Given. — The sighting drills will be given to 
all soldiers who have not qualified as " marksmen " or better in 
the preceding target year. 

20. Purpose. — Sighting drills. 

(a) To show how to align the sights properly on the mark. 
.(&) To discover and demonstrate errors in sighting, 
(c) To teach uniformity in sighting. 

21. Apparatus and Its Use — Sighting Bar.-— (See PI. I.) 
To consist of : 

(a) A bar of wood about 1 inch by 2 inches by 4 feet, with a 
thin slot 1 inch deep cut across the edge about 20 inches from 
one end. 

( & ) A front sight of tin or cardboard i inch by 3 inches tacked 
to the end nearer the slot and projecting 1 inch above bar. 

(c) An eyepiece of tin or cardboard 1 inch by 3 inches tacked 
to the other end of, and projecting 1 inch above, the bar, with 
a very small hole (0.03 inch) \ inch from top of part projecting 
above the bar. 

(d) An open rear sight of tin or cardboard 1^ by 3 inches, 
with, a U-shaped notch f inch wide cut in the middle of one of 



26 



MACHINE-GUN FIRING MANUAL. 



the long edges. This is placed in the slot on the bar. A slig] 
bend of the part of the tin fitting in the slot will give enough 
friction to hold the sight in any part of slot in which it is 
placed. 



Eye piece 




Rear sight 



Front 
sight 



Plate 1. 



MACHINE-GUN FIRING MANUAL. 27 

(e) A peep rear sight of tin or cardboard 3 by 3 inches, with 
a peep hole f inch in diameter cut in the center. This replaces 
the open sight when the peep sight is shown. 

Carefully blacken all pieces of tin or cardboard and the top 
of the bar. Nail the bar to a box about 1 foot high and place 
on the ground, table, or other suitable place. Then adjust the 
open or peep rear sight in the slot and direct the bar upon a 
bull's-eye (preferably a Y target) placed about 5 yards from the 
bar. No other than the sight desired can be seen. Errors, etc.. 
are shown by manipulating the open and peep rear sights. 

22. Takget for Sighting Drill and Its Use. — Nail a plank 
to a stake or w r all at the proper height from the ground — about 
30 inches for heavy-type gun and about 12 inches for light type 
of gun. Fasten a sheet of paper to the plank. Place the gun 
in position 100 yards from target, so that the gun is canted 
neither to right nor left, and without touching the gun sight it 
near the center of the blank sheet of paper. The distance of 
100 yards places the objective far enough away to insure that 
the sights and the target can not all be seen distinctly and at 
the same time with a single focus of the eye, thus forcing the 
individual to focus the eye on the objective in order to secure 
accurate results. Changes in the line of sight are made by 
changing the elevating and traversing gears. Take the prone 
position with elbows on the ground, hands supporting the head. 
A soldier acting as a marker is provided with a pencil and a 
small rod bearing a disk of black cardboard about 4 inches in 
diameter, pierced in the center with a hole just large enough 
to admit the point of a lead pencil. The soldier sighting directs 
the marker to move the disk to the right, left, higher, or lower 
until the line of aim is established, when he commands " Mark " 
or " Hold." At the command " Mark," being careful not to 
move the disk, the marker records through the hole in its 
center the position of the disk and then withdraws it. At the 
command " Hold " the marker holds the disk carefully in place 
without marking until the position is verified by the instructor* 
and the disk is not withdrawn until so directed. 



28 MACHINE-GUN FIRING MANUAL. 

23. Line of Sight. — With the open sight the line of sight 
is determined by a point on the middle line of the notch of the 
rear sight and the top of the front sight. With the peep sight 
the line of sight is determined by the center of the peep and the 
top of the front sight. 

24. Point of Aim. — The soldier will be informed that to give 
the greatest uniformity a point just below the mark, and not 
the mark, is taken as the point of aim, as it is impossible to 
always know, if touching the mark with the top of the front 
sight, how much of the front sight is seen ; that the term " on 
the mark or bull's-eye " will be understood to mean an aim, 
taken just below the mark, showing a fine line of light between 
the mark and the top of the front sight. 

25. The Normal Sight. — Look through the rear sight notch 
at the bull's-eye or mark and bring the top of the front sight 
on a line with the top of and in the center of the rear sight 
notch and aligned upon the point of aim. (See fig. 1, pi. 2.) 

26. The Peep Sight. — Look through the peep hole at the 
bull's-eye or mark and bring the top of the front sight to the 
center of the aperture and aligned upon the point of aim. ( See 
fig. 2, pi. 2.) 

The soldier should be informed that regular results in fir- 
ing can be obtained only when the same amount of front 
sight is taken each time, and that this can be done only by 
using the normal sight with the open notch or the peep sight in 
the manner described above. He should understand that the 
effect of taking less than the normal amount of sight is to cause 
a point lower than that aimed at to be struck, and that taking 
too much of the front sight causes a higher point to be struck. 

Although men Will be found occasionally who can get excel- 
lent results by using the fine sight (fig. 3, pi. 2), the average 
man can not, and this form of sighting is not recommended. 
The so-called full sight should not be taught under any circum- 
stances. If shown to the men at all, it should be for the pur- 
pose of pointing out a fault to be carefully avoided. 



MACHINE-GUN FIRING MANUAL. 29 

Remarks. — The eye can be focused accurately upon objects 
at but one distance at a time ; all other objects in the field of 
view will appear more or less blurred, depending on their dis- 
tance from the eye. This can readily be seen if a pencil is 
placed in the field of view near the eye while looking at some 
distant object. The pencil will appear blurred. This is the 
condition met with by the normal eye in sighting a gun. If the 
eye is focused on one of the three points — the bull's-eye ; the 
front sight, or the rear sight — the other two will appear blurred. 
This blurring effect is best overcome by using the " peep sight," 
as though looking through a window, and focusing the eye on 
the bull's-eye. The blurring of the peephole will be concentric, 
giving a clear and easily defined center. The blurring of the 
front sight will be less, but symmetrical on both sides, with 
very little blur on the top. It can be readily and naturally 
brought to the center of the peephole. Variations in light have 
less effect on the peep than on the open sight. 

But the limited field of view and lack of readiness in getting 
a quick aim with the peep sight limit its use to those stages 
of the combat when comparative deliberation will be possible. 
In the later stages of the battle — especially when a rapid fire 
is to be delivered — the open sight will, in most cases, be used. 
In this case the normal sight should be used, as the horizontal 
line at the top of the notch of the rear sight affords a good 
guide for regularity. 

Whatever sight is used, the eye must be focused on the bull's- 
eye, or mark, not on the front or rear sight. 

27. Methods of Sighting. — The methods in sighting machine 
guns are not the same for the different types of gun. 

The heavy gun (tripod mount) is laid on the target, i. e., 
sighted at the target before firing commences, but no attempt 
is made to keep the eye on the sights while firing, the aim being 
corrected between bursts or strings. On the other hand, with 
the light gun the general alignment of sights is maintained 
during the firing. 



30 MACHINE-GUN FIRING MANUAL. 



bL. 





FIG.3. 



^4 i / f*g.S. 



Plate 2. 



MACHINE-GUN FIRING MANUAL. 



31- 




Plate 3. 



32 MACHINE-GUN FIRING MANUAL. 

FIRST EXERCISE. 

28. Using illustrations, describe the normal sight and the 
peep sight. 

29. Using the sighting bar, represent the normal sight and the 
peep sight and require each man in the squad to look at them. 

30. Using the sighting bar, describe and represent the usual 
errors of sighting and require each man in the squad to look 
at them. 

SECOND EXERCISE. 

31. Using the method described in paragraph 22, require 
each man to direct the marker to move the disk until the gun 
is directed on the bull's-eye with the normal sight and com- 
mand " Hold." The instructor will verify this line of sight. 
Errors, if any, will be explained to the soldier and another trial 
made. If he is still unable to sight correctly, the first exercise 
will be repeated. 

Soldiers will sometimes be found who do not know how to 
place the eye in the line of sight ; they often look over or along 
one side of the notch of the rear sight and believe that they 
are aiming through the notch because they see it at the same 
time that they do the front sight. This error will probably be 
made evident by the preceding exercise. Some men in sighting 
will look at the front sight and not at the object. As this often 
occasions a blur, which prevents the object from being distinctly 
seen and increases both the difficulties and inaccuracies of 
sighting, it should be corrected. 

32. Repeat the above, using the peep sight. 

THIRD EXERCISE. 

33. Using the method described in paragraph 22, require 
each man to direct the marker to move the disk until the gun 
is directed on the bull's-eye with the normal sight and com- 
mand " Mark " ; then, being careful not to move the gun or 
sights, repeat the operation until three marks have been made. 



MACHINE-GUN FIRING MANUAL. 33 

(a) The Teiangle of Sighting. — Join the three points de- 
termined as above by straight lines, mark with the soldier's 
name, and call his attention to the triangle thus formed. The 
shape and size of this triangle will indicate the nature of the 
variations made in aiming. 

(&) Abnoemal Shapes, Causes. — If the longer sides of the 
triangle approach the vertical (see fig. 5, pi. 2), the soldier 
has not taken a uniform amount of front sight. If the 
sides of the triangle are more nearly horizontal (see fig. 4, 
pi. 2) the errors were probably caused by not looking through 
the middle of the notch or not over the top of the front sight. 
The instructor will explain that the sighting gains in regularity 
as the triangle becomes smaller. 

(c) Verifying the Triangle. — If the sides of the triangle 
are so small as to indicate regularity in sighting, the instructor 
will mark the center of the triangle and then place the center of 
the bull's-eye on this mark. The instructor will then examine 
the position of the bull's-eye with reference to the line of sight. 
If the bull's-eye is properly placed with reference to the line of 
sight, the soldier aims correctly and with uniformity. If not 
so placed, he aims in a regular manner but with a constant 
error. 

As a final test of the ability of the individual to use the sights 
with uniformity and precision, he should be required to make 
three " sighting triangles " in succession, no one of these tri- 
angles to be of such size that it can not be contained within the 
circumference of a circle 1 inch in diameter. 

A convenient gage for measuring these triangles may be im- 
provised by boring a 1-inch hole in a thin piece of sheet metal. 
By bending one edge of this piece of metal to form a convenient 
handle, this gage may be applied easily to the face of the sur- 
face on which the triangle was made and thus the instructor 
may determine by a quick inspection whether the result is 
within or without the prescribed limit. 
106191°— 17 3 



34 



MACHINE-GUN FIRING MANUAL. 



34. (d) Causes of Errors. — If the bull's-eye is directly 
above its proper position, the soldier has taken in aiming too 
little front sight, or if directly below too much front sight. If 
directly to the right or left, the soldier has not sighted through 
the center of the rear-sight notch and over the top of the front 
sight. If to the right he has probably either sighted along the 
left of the rear sight notch or the right side of the front sight, 
or has committeed both of these errors. If the bull's-eye is too 





Plate 4. 

Sighting gage. 

far to the left, he has probably sighted along the right of the 
rear sight notch or to the left of the front sight or has combined 
both of these errors. 

If the bull's-eye is placed with reference to its proper posi- 
tion diagonally above and to the right, the soldier has probably 
combined the errors which placed it to high and too far to the 
right. Any other diagonal position would be produced by a 
similar combination of vertical and horizontal errors. 

As the errors thus shown are committed when the gun is 
fixed in position, while that of the target or bull's-eye is altered, 



MACHINE-GUN FIRING MANUAL. 3£ 

the effect will be directly opposite to the changes in the loca- 
tion of a hit in actual fire, occasioned by the same errors, when 
the target will be fixed and the gun moved in aiming. 

After the above instruction has been given to one man, the 
line of sight will be slightly changed by moving the gun or by 
changing the elevating and traversing gears, and the exercises 
similarly repeated with the other men of the squad. 

85. Repeat the third exercise, using the peep sight. 

FOURTH EXERCISE. 

36. This exercise is a demonstration of the effect of canting 
the gun. The soldier must be impressed with the necessity of 
keeping the sights vertical when aiming, and not canting the 
gun to right or left. Explain to the soldier that if the gun is 
canted to the right, the bullet will strike to the right and below 
the point aimed at, even though the gun be otherwise correctly 
aimed and the sights correctly set. Similarly, if the gun is 
canted to the left, the bullet will strike to the left and low. 
This can be explained by showing that the elevating gear fixes 
the height of the point where the bullet will hit the target, and 
the traversing gear fixes the point to the right or left ; i. e., 
elevating gives vertical and traversing horizontal effects. Let a 
pencil (or rod) held vertical represent the elevation; now if 
the pencil is turned to the right 90°, or horizontal, all of the 
elevation has been taken off, causing the shot to strike low 
and changed into traversing, causing the shot to strike to the 
right. Emphasis should be laid on the fact that this effect of 
canting increases with the distance from the target. 

37. Other Exercises. — If time permits, the instructor may 
devise other exercises which suggest themselves as useful and 
beneficial to his men. The following are examples : 

(a) In strong sunlight make a triangle by sighting, using a 
gun having sights worn bright. Then being careful not to move 
the gun blacken sights and make another triangle. Use dotted 
lines for the triangle made with bright sights and full lines for 
the triangle made with blackened sights. The position and size 



36 MACHINE-GUN FIRING MANUAL. 

of the two triangles will plainly show the advantage of black- 
ened sights. 

( o ) In strong sunlight make a triangle by sighting ; then, be- 
ing careful not to move the gun, make another triangle having 
first shaded the target and the man sighting. The relative posi- 
tion of the triangles will show the importance of knowing the 
effects of varying degrees of light. 

POSITION EXEECISES. 

38. The instructor illustrates the proper firing position and 
explains the reasons for taking that particular position in pref- 
erence to any other. 

It is not considered desirable nor necessary to prescribe hard 
and fast rules as to all the details of all of the firing positions 
with the defferent types of guns. 

The illustrations of positions given herein show those posi- 
tions that have given the best results, and also show the most 
common faults. 

39. Benet-Meecie Rifle. 

correct position. 



: 




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un 














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_ _ ~ - _ 



Plate 5. 



MACHINE-GUN FIRING MANUAL. 

CORRECT POSITIONS. 



37 




Plate 6. 




Plate 7. 



38 



MACHINE-GUN FIRING MANUAL. 



CORRECT POSITION. 




Plate 



CORRECT POSITION. ; 




Plate 9. 



40 



MACHINE-GUN FIRING MANUAL. 




MACHINE-GUN FIRING MANUAL. 



41 



CORRECT POSITION. 





"~"l;.J,r-i 


■ 






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*%Jmgm 






.. ■ , . .', ... 


$g*^ e "" A :"",^ .^ 




;3f - :? pf ;: 55;:T 1%Sf Sf 


^ . , 


pi,:::., 
* *- -$ 


If^^flil"^ 


* j* * 


tfvjk-;' v" 


- If * 





Plate 11. 
On hillside. 



MACHINE-GUN FIRING MANUAL. 




Plate 12. 
Body inclined to right — will cause gun to traverse. 



MACHINE-GUN FIRING MANUAL. 



43 



INCORRECT POSITION. 




Plate 13. 
Body inclined to left — will cause gun to traverse. 



44 



MACHINE-GUN FIRING MANUAL. 



INCORRECT POSITION. 




Plate 14. 
Body inclined to left — will cause gun to traverse. 



MACHINE-GUN FIRING MANUAL. 



45 



INCORRECT POSITION. 




Plate 15. 
Piece canted on hillside. 



INCOEEECT POSITION. 




Plate 16. 
Body inclined to right — head not in position to see sights. 
46 



MACHINE-GUN FIRING MANUAL. 



4T 







48 



MACHINE-GUN FIRING MANUAL. 



40. Lewis Machine Gun. 



W ^BBSTi 


^ 


&&. "" 




bu. ^ -^SSlfcl 









Plate 18. 



Showing butt tang, disk on rear sight slide and front sight cover 
attached. 



CORRECT POSITION * 




Plate 19. 
Body in prolongation of bore, feet slightly spread. 
106191°— 17 4 49 



50 



MACHINE-GUN FIRING MANUAL. 



CORRECT POSITION. 




Plate 20. 
Front view ; guard gripped with both hands, no exposure of body or legs. 



INCORRECT POSITION. 




Plate 21. 

Body at an angle with respect to the bore (as when firing infantry 
rifle). 51 



S2 



MACHINE-GUN FIRING MANUAL. 



INCORRECT POSITION. 




Plate 22. 
Front view ; exposure of body and leg. 



MACHINE-GUN FIRING MANUAL. 



53 




Plate 23. 



Reloading. Loader changing magazines from prone position of gunner's 
left. Working on the gunner's left, the loader can rest on his left 
elbow and manipulate the magazine catch with his right hand from 
the prone position ; further, he is not distracted by the empty car- 
tridges which are ejected with considerable force from the right side 
of the receiver and slightly to the rear. 



54 



MACHINE-GUN FIRING MANUAL. 







*• 



Plate 24. 



A correct position on a hillside. Field mount canted, barrel turned in 
yokes, bringing sights vertical. 



MACHINE-GUN FIRING MANUAL. 



55 




*£*ij|||£ 




Plate 25. 



Correct firing around corner of building. Field mount legs in front of 

covner. 



MACHINE-GUN FIRING MANUAL. 




Plate 26. 



Correct firing over parapet of trench. Field mount reversed to permit 
wide distribution. Loader in incorrect position — fully exposed. 



MACHINE-GUN FIRING MANUAL. 



57 




1 f!t 






Plate 27. 
Correct firing over parapet. Front view. 



58 



MACHINE-GUN FIRING MANUAL. 




Plate 28. 



Correct firing over parapet of trench. Barrel resting on parapet, field 
mount removed. Note loader taking advantage of cover and reducing 
visibility. 



MACHINE-GUN FIRING MANUAL. 



59 




Plate 29. 
Correct firing from position in a tree. 



^0 MACHINE-GUN FIRING MANUAL. 

41. With the Benet-Mercie, uniform support for the piece 
is secured to a great degree by the use of the barrel rest and 
the elevating mechanism. This uniformity is not absolute, how- 
ever, unless the position of the barrel rest relative to the barrel 
is also uniform. 

The most uniform results are obtained when the legs of the 
barrel rest — looking at the piece from the side — are at right 
angles to the axis of the bore. When the legs are inclined to 
the rear from their point of attachment to the barrel, the re- 
sulting shot group will be high, and when they are inclined to 
the front the shot group will be low. A uniform position of 
these legs may be secured by the use of the leather thong sup- 
plied for this purpose. 

It may be necessary at times to dispense w T ith the use of 
the elevating mechanism and the muzzle rest, and support the 
rifle merely on the parapet, a sandbag, or some other improvised 
mount. The use of such a support usually will be at short 
ranges wiiere slight errors of elevation will be of little moment. 
In firing in this manner more satisfactory results are obtained 
when the point of support is at the balance of the piece than 
elsewhere. 

When the tripod mount is not used the degree and direction 
of resistance to the recoil is dependent upon the position of 
the firer. 

With the infantry rifle one is taught to incline the body to 
the left when firing in the prone position. 

With the automatic rifle, either Benet-Mercie or Lewis, such 
a position results in the impact being to the left of the objective, 
as the recoil forces the shoulder to the right as well as to the 
rear, and the shots come in such quick succession that there 
is insufficient time between shots for the firer to resume or 
recover his original position. 

Therefore the firer's body should be inclined neither to the 
right nor the left, but should be directly in prolongation of 
the plane of fire. This will assure the movement of the shoulder 



MACHINE-GUN FIRING MANUAL. 61 

being in the same direction as the recoil, i. e., straight to the 
rear. (See pi. 7.) 

Additional steadiness is secured by pressure of the butt 
against the shoulder, this pressure being exerted by the right 
arm and, at times, by the left also. 

In using the infantry rifle one is taught to seek a good posi- 
tion and then attempt to hold steadily by drawing his rifle 
back hard against the shoulder. 

With the automatic rifle similar methods are used when the 
piece is fired from a parapet or sandbag rest. This he accom- 
plishes by forcing the shoulder forward against the butt and 
at the same time drawing the piece back against the shoulder 
by pressure with the arms. 

Care is taken in the beginning not to keep the individual 
too long in the firing position, for it is quite fatiguing to the 
untrained man. 

Speed is next sought — never at the expense of accuracy, how- 
ever — and the exercise continued until the desired standard is 
reached. 

Speed and accuracy is next sought in taking the firing posi- 
tions from the standing and from the crawling position. 



62 



MACHINE-GUN FIRING MANUAL. 



42. VlCKERS. 



POSITION FOR FIRING. 



Hi 


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*> 






V,.: 








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v ' " " " - 






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■■ v -* •> -* * 




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pPB^ii 


~ : • * ~ 


.;...,-*,„" 


, 



Plate 30. 
Gun set up on fairly steep reverse slope. 



MACHINE-GUN FIRING MANUAL. 



6& 



POSITION FOR FIRING FROM ENTRENCHMENT- 




Plate 31. 
Front legs may be set into parapet or rest on top of parapet. 



64 



MACHINE-GUN FIRING MANUAL. 



INCORRECT SET-UP. 




Plate 32. 



Top carriage too far to front ; vertical axis of mount inclined to front 
and traversing surface not level. 



MACHINE-GUN FIRING MANUAL. 



65 



CORRECT POSITION FOR EMERGENCY FIRE TO LEFT FLANK. 



i/' if • 

1 - 






HH 


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Plate 33. 
Gun released from elevating gear but still supported by tripod. 
106191°— 17 5 



66 



MACHINE-GUN FIRING MANUAL. 



CORRECT POSITION FOR FIRING X T P VERY STEEP SLOPE. 




Plate 34. 
At top of high buildings, at aeroplanes, etc. 



MACHINE-GUN FIRING MANUAL. 



67 



CORRECT POSITION "FOR FIRING. 







. 1 -■- 


^^^L '"* 


""""";' ' s~'"\ 




31 






' 



Plate 35. 



Gun set up on rough ground sloping to the front and left. Gunner 
utilizing slope of ground for partial cover. 



68 



MACHINE-GUN FIRING MANUAL. 



CORRECT POSITION FOR FIRING. 




■•"•■-.; . . : ■■:■■■ ■ ■ ■ . ■■■■■ ,■■■■ . ■ -.:.:■ ..: . . ■■,• ■ ■ ' .■•■.. 



Plate 36. 



Mount in intermediate position. Squad leader kneeling. Gunner in 
crouching sitting position. Loader and No. 3 prone. 



MACHINE-GUN FIRING MANUAL. 

CORRECT POSITION FOR FIRING. 



69 




Plate 37. 

Mount in highest normal position. Crew kneeling. 

Squad leader in rear. 

Gunner on seat. 

Loader on right side of gun. 

No. 3 on left side of gun. 

No. 4 bringing up ammunition. 

No. 5 and No. 6 (not shown), ammunition bearers. 



70 MACHINE-GUN FIRING MANUAL. 

CORRECT POSITION FOR FIRING. 




Plate .38. 

Prone, lowest position of mount. Gunner's head rests on loader's 

left leg. 



CORRECT POSITION FOR FIRING. 




Plate 39. 

Prone, lowest position of mount. Gunner's head rests on loader's 

left leg. 



MACHINE-GTJN FIRING MANUAL. 



71 



INCOKEECT SET-UP. 




Plate 40. 
Left front leg too much inclined, throwing vertical axis of mount to left. 



72 



MACHINE-GUN FIRING MANUAL. 



43. Maxim. 

Feet flat on ground. Weight of body entirely on seat. Elbows 
on knees. Both hands grasping handles firmly, both thumbs free 
to press trigger. Right thumb on safety catch, left thumb on 
trigger. Body inclined forward so as to bring the eye as near 
the rear sight as possible. Pull straight down with considerable 
force on the handles while firing and hold the gun firmly. 

COEKECT POSITION. 




It is impossible for the gunner to maintain his line of sight 
while firing, but men must not be allowed to acquire the habit 
of throwing the body to the right or left or to lean back to the 
full extent of the arms. All these movements allow the gun to 
vibrate more freely than when held in the correct position. 



MACHINE-GUN FIRING MANUAL. 



73 



INCOREECT POSITION. 



=.'■-.""■ 


mi 


me: iWk -3 


i ...,.,.., § 



Plate 42. 
Trail out. 



74 



MACHINE-GUN FIRING MANUAL. 



INCORRECT POSITION. 





IP" 
















Ki^-^ 






1 






m ^k uw*«* ^«*#^i 


' 








0^<- 




f> 


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^^ 






W&m 


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Ii\ -~ • 


- 5 ,,:■ 


EK5 




S3P^*^^ 



Plate 43. 
Trail in. 



MACHINE-GUN FIRING MANUAL. 



75 



Eye too far from rear sight. Weight thrown so far to rear as 
to cause excessive Jump (vibration) at muzzle. Gun not firmly 
held. No power to hold down on handles. 



INCOREECT POSITION. 




44. The instructor's illustration and explanation being com- 
pleted, he requires the men undergoing instruction to take the 
firing positions, supervising and correcting until the position is 
perfect in every detail. With short intervals of rest, this is 
repeated until "the position can be taken with accuracy and 
uniformity. 



76 MACHINE-GUN FIRING MANUAL. 

AIMING EXERCISES. 

FIRST EXEKCISE. 

45. The Use of the Elevating Mechanism. — A target is 
prepared with several aiming points at different heights, on 
the following order : 

(1) (2) 

(3) 

(4) (5) 

Plate 45. 

The target is set up at 27|- yards and the various aiming 
points are numbered in such a manner that they can be distin- 
guished easily from the position of the gun. 

The instructor explains the proper method of moving the 
aim in vertical and horizontal directions, and that the object 
of this exercise is to familiarize the soldier so thoroughly with 
the manipulation of the weapon that false motions in changing 
aim are eliminated. 

The instructor places himself in a position from which he can 
detect any errors of the movement of the line of aim, causes the 
man undergoing instruction to take the firing position, and then 
directs him to "Aim at No. 1 (2, 5, 4, etc.)." 

In executing the command of the instructor there is no at- 
tempt at first at rapidity of movement. Care is taken that 
the changes made are not so great as to carry the line of aim 
beyond the aiming point and thus necessitate a further change. 

When an ability to manipulate the weapon without hesita- 
tion or error has been attained then speed is sought and the 
exercise is continued until the desired degree of proficiency is 
reached. 



MACHINE-GUN FIRING MANUAL. 

SECOND EXEKCISE. 



77 



46. Verifying the Use of the Elevating Geae. — The sol- 
dier being in the firing position and the line of aim being di- 
rected elsewhere than at the desired objective, the instructor 
directs "Aim at No. 5 (1, 2, 3, etc.)." 




Pinal point 
"of aim 



Initial point 
of aim 



Plate 46. 
Correct travel of line of aim. 

In carrying out the directions of the instructor the soldier 
causes the line of sight to approach his target by one large step 
in elevation and traverse, which brings the line of aim close to 
the final point of aim, and then executes a second small step to 
complete the correction, thus : 

The instructor follows closely the movements of the soldier 
in obtaining his line of aim. If the line should be as shown in 
Plate No. 47 below, the incorrect method is pointed out to the 
soldier. 



78 MACHINE-GUN FIRING MANUAL. 



T 



Initial pointi 



i 

U I 



of aim. ^j | 



IB 



I 



* £inal point 

4-3 1— T f aim. 

Plate. 47. 
Incorrect travel of line of aim. 

The soldier started in by elevating the piece instead of de- 
pressing it indicating a lack of familiarity with the gear. When 
he arrived at thd point "A," the muzzle was moved to the left 
before it was moved to the right. The travel was also con- 
tinued to the point "B." It often will be easier, and perhaps 
necessary, when directing the piece on an objective that is be- 
low the initial point of aim, to bring the line of aim a little 
below the objective and then raise it to its proper position. To 
allow the line of aim to fall as low as the point "C," however, 
is unnecessary and may be accounted for by the fact that it 
was directed so far to the right of the objective that the latter 
was obscured by the sight cover or that the firer was not suffi- 
ciently practiced in the use of the gear to have it under per- 
fect control. In each case the instructor determines the cause 
of the error by observation, and explains its nature and the 
method of correcting it to the soldier. 

This exercise is continued until satisfactory results are ob- 
tained. 

When the soldier can distribute his fire in a satisfactory 
manner on the straight horizontal line in either direction, the 



MACHINE-GUN FIRING MANUAL. 79 

arrangement of the figures is changed so as to represent 
straight diagonals and finally irregular lines. 

When accuracy has been attained, speed is sought and the 
soldier is considered proficient when he can distribute his aim 
with accuracy on an irregular line and at a speed of about 5 
seconds per aiming point. 

The various classes of mounts are used in this as in the 
preceding exercise. 

THIRD EXERCISE. 

47. Practice in Searching Fire. — (Target MGB.) Search- 
ing fire is fire distributed in the direction of depth. It may be 
used for the purpose of distributing fire throughout a deep 
target or for the purpose of increasing the depth of beaten zone 
in order to compensate for probable errors in the estimation of 
the elevation or the range. Whatever its purpose, its execution 
is the same. 

The unit of measure, by which the amount of searching is 
announced, is the mil. For this instruction, marks (heavy lines 
or pasters) are placed upon the target indicating intercepts of 
2, 4, 6, and 8 mils. 

When the mechanism is used to cause elevation or depression, 
it is sought first to cultivate the soldier's dexterity in judging 
with accuracy the various fractions of a turn of the elevating 
handwheel, one-eighth, one-quarter, etc., and consider these 
turns in terms of mils. In machine guns not fitted with the 
elevating mechanism, this data is determined in terms of the 
front sight or the aperture in the rear sight. 

The soldier having determined the data necessary to effect 
the search of any ordered number of mils, the instructor di- 
rects that aim be taken on a target on which the mil intercepts 
are not marked. The order is then given " Target No. 1, search 
4 mils up (or so many mils down)." The soldier aims at the 
target and calls " mark " as an indication to the instructor 



80 MACHINE-GUN FIRING MANUAL. 

that he believes the gun to be correctly pointed at the target. 
By means of the elevating gear or a movement of his shoulder 
in the case of a rifle not fitted with elevating gear he then ele- 
vates or depresses the piece until he believes it pointed at the 
proper angle of 2 mils above or below the target. The aim is 
then verified by the instructor. 

This aiming at intervals of 2 mils is continued until the 
whole amount of the searching is completed. The instructor 
should see that a steady hold and correct change of elevation 
has been made every time the soldier calls " mark." 

FOURTH EXERCISE. 

48. Practice in Distributed Fire. — (Target MGB.) When 
the soldier has attained proficiency in the preceding exercise, 
practice is begun in distributed fire. 

The target at first represents prone skirmishers in a straight 
horizontal line. This target is set up at 27| yards distance. 
The figures in the targets are reduced to scale, so that they 
have the same appearance as a line of the density of one man 
per yard at 300 yards. 

The soldier is required to aim at each figure in succession 
from enemy left to enemy right and calls " mark " when he 
considers his aim at each to be correct. The instructor veri- 
fies the soldier's aim in each case with the aiming device. 

The exercise is repeated, the aim moving from enemy right 
to enemy left. 

The lateral interval between aiming points should be about 
2| mils. 

Note. — With the automatic machine rifle, model of 1909, a distribu- 
tion of about 2| mils may be obtained thus : 

1. Bring the normal sight to bear on an object. 

2. Without moving the piece, shift the eye to right or left until 
the tip of the front sight approaches the corner of the rear sight 
triangle. The prolongation of this line will strike a point approxi- 
mately 3 mils from the original aiming point. 



MACHINE-GUN FIRING MANUAL. 



81 



FIFTH EXERCISE. 

49. Seakching With Distkibution. — ( Target MGB. ) Search- 
ing fire is now combined with distributed fire. Targets are the 
same as for distributed fire without searching. The path of the 
point of aim is verified in the same manner as for distributed 
fire. The point of aim should not go above or below the 
control line more than the number of inches equivalent to 
the amount of searching in mils which was directed. As in dis- 
tributed fire the horizontal interval between aiming points 
should be about 2i mils. 

SIXTH EXERCISE, 

50. Searching With Distribution — Diagonal. — (Target 
MGA. ) Aim is directed at the u, per enemy right paster of an 
assigned section of target MGA. The instructor takes a position 
to verify the travel of the line of aim, the soldier directs the 
aim successively at the lower aiming point in the next row to 
the left, then diagonally upward, downward, etc., until the 
edge of the section is reached. The aim is then moved to the 
point vertically above (or below) and then directed successively 
at each point omitted, returning to the starting point. 

The gunner calls "mark" as his aim is directed at each 
aiming point and the instructor notes whether or not the line 
of aim is following the path shown in plate 48. 




Plate No. 48. 



Travel, line of aim. Searching with distribution, diagonal. 

Note. — When using a tripod mount, due to mechanical difficulties 
and the advantage in approaching- an aiming point from beneath, speed 
and accuracy will seldom be gained by manipulating the traversing 
and elevating gear simultaneously. 

106191°— 17 6 



S2 MACHINE-GUN FIRING MANUAL. 



SEVENTH EXERCISE. 






51. Reloading. — Rate of fire is dependent to a certain ex- 
tent upon the rapidity with which the piece is reloaded. Hence 
the importance of training in this particular. 

This practice should include the case of the soldier firing and 
reloading without assistance and that of acting as assistant 
and reloading while another fires. The instructor illustrates 
the positions to be taken and the methods of reloading in each 
case. 

The exercise is executed with dummy cartridges. 

The gun is loaded with one dummy cartridge in the last 
recess of the cartridge container. The soldier directs his aim 
at a given point and calls " mark." The cartridge container 
is then replaced by another loaded with a single dummy car- 
tridge in the first recess and the soldier again directs his aim 
at the same target calling " mark." 

At first all attention is paid to details, to the precision and 
sequence of movements, speed being demanded only as dexterity 
is gained. 



CHAPTER IV. 
USE OF INSTRUMENTS. 

52. Training in the use of instruments is a part of garrison 
work. The scheme of instruction in all instruments follows the 
same general idea. First, the instrument is studied as a piece 
of machinery, using the authorized handbook or some standard 
textbook as a guide to the theory of the instrument, its nomen- 
clature, the mechanical principles on which it operates, methods 
of adjustment, and directions for its use. Second, practice in 
adjusting the instrument and in using it with a view to first 
obtaining the utmost precision of measurement and then attain- 
ing the greatest possible speed. 



MACHINE-GUN FIRING MANUAL. 83 

The following outline of training in the use of instruments is 
suggested : All members of a machine-gun organization should 
be thoroughly instructed in each instrument with which the 
organization is provided, and the men who are to habitually 
use a certain instrument should have a maximum amount of 
training in its use. 

53. Field Glasses. — Adjustment for interpupillary distance 
and for focus. Use in standing, sitting, and prone positions and 
with rests. Reading printed signs at maximum distances. 
Picking up designated objects whose general direction is indi- 
cated by the instructor. Counting indistinct and distant ob- 
jects. Determining the character of distant and indistinct ob- 
jects. 

EXAMPLES. 

1. Object for observation, a group of about 10 men in mixed 
uniforms at such a distance they can just be distinguished with 
the naked eye as men. Problem: Pick up the group with the 
glasses, note how many men are wearing hats, caps, fatigue 
clothes, O. D. shirts, etc. How many are standing, sitting, 
prone, etc.? Can you recognize any individuals by name? 

2. Object for observation, a line of freight cars at such a dis- 
tance that the lettering on the cars can not be read without 
glasses. Problem: Write down all the words and numbers that 
you can make out on each car. In recording this data draw a 
rectangle to represent each car and copy the words and num- 
bers exactly as they appear on the car. 

54. Range Finders. — Setting up and handling the instru- 
ment. Adjustments for focus, halving, and distance. Measure- 
ment of range to well-defined points. Measurements of indis- 
tinct objects. Use of instrument in vertical position. Range on 
moving targets. 

EXAMPLES. 

1. Five well-defined points, such as poles, corner of a build- 
ing, railroad-crossing signs, etc., are chosen by the instructor. 



84 MACHINE-GUN FIRING MANUAL. 

Ranges should be between 500 and 2,000 yards. The soldier is 
required to make three ( or five ) measurements of the range to 
each of these points, closing the range scale slide each time 
while taking the measurement. He will then calculate the mean 
of his readings by adding the distances together and dividing 
by the number of measurements. 

2. Stake out a straight route about 1,000 yards long on ground 
that is visible from the position of the range finder. The dis- 
tant end of this route should be about 1.50Q yards and the nearer 
end about 500 yards from the range finder. A soldier is di- 
rected to walk over this route at a uniform rate of speed. The 
soldier under instruction takes the range to the moving soldier 
whenever ordered to by the instructor. The instructor can 
check the accuracy of these measurements if he knows the 
range to each end of the route and notes the time at which the 
moving soldier starts, , the time of each observation, and the 
time of reaching the end of the route. 

55. Mil Scale. — Measuring horizontal and vertical and in- 
clined angles in mils. Use of the mil rule for obtaining any 
one of the quantities mils, width or range, when the other two 
are given. Auxiliary aiming point data. Combined sights. 

Textbook, the handbook describing the particular type of mil 
scale used, 
from the flagstaff. 

EXAMPLES. 

1. A telegraph pole in the distance, known to be 30 feet high, 
is found by measurement with the mil scale to subtend an angle 
of 22^ mils. What is the range? 

50. Sights. — The study of tangent and telescopic sights as 
instruments will be confined to their theory, nomenclature, 
methods of adjustment and setting, and their care under field 
conditions. 

57. Prismatic Compass. — Textbook, any work on topography. 
Obtaining magnetic declination. Precautions about iron in 



MACHINE-GUN FIRING MANUAL. 85 

vicinity. Measurement of bearings to distant points. Reloca- 
tion from map by compass readings. 

EXAMPLES. 

1. Using the prismatic compass, determine the angle in mils 
subtended by the barracks of the machine gun company as seen 
from the flagstaff. 

2. Here is a map showing that white church [pointing] and 
that railroad crossing [pointing]. Using the prismatic compass, 
determine our present position on the map. 

58. Clinometer and Hand Level.- — Textbook, any work on 
topography. Adjustments. Determining a level line. Measur- 
ing slopes. Measuring angles of site. 

EXAMPLES. 

1. Stake out, using the hand level, a level line around this 
hill, beginning at this point. 

2. Determine the angle of site to the base of that tree, to that 
white rock, etc., using the clinometer for your measurements. 



CHAPTER V. 
THE DETERMINATION OF RANGES. 

59. A maximum fire effect without an accurate determination 
of the range is impossible. A definite method in the determina- 
tion of ranges is essential to accuracy. 

Ranges may be determined, before fire is opened, by one of the 
following methods : 

(a) Estimating distances on the ground by eye; 

( b ) Taking the range from a map of large scale ; 

(c) Obtaining it direct from infantry or artillery already 
engaged ; 

(d) Measuring the range directly on the ground ; 

(e) Estimating distance by sound; 



86 MACHINE-GUN FIRING MANUAL. 

(/')-" Ranging fire (par. 219) ; 
(g) Range finders. 

60. (a) Estimating Distances. — Skill in estimating dis- 
tances can be attained and improved by training. To estimate 
distance by the eye with accuracy it is necessary to be familiar 
with the appearance, as to length, of a unit of measure which 
can be compared mentally with the distance which is to be esti- 
mated. The most convenient unit of length is 100 yards. To 
impress upon the soldier the extent of a stretch of 100 yards 
two posts 100 yards apart, with short stakes between to mark 
each 25 yards, should be placed near the barracks or on the 
drill ground, and the soldier required to pace off the marked 
distance several times, counting his steps. He will thus learn 
how many of his steps make 100 yards, and will become familiar 
with the appearance of the whole distance and of its fractional 
parts. 

Next a distance of more than 100 yards will be shown him 
and he will be required to compare this distance with the 
100-yard unit and to estimate it. Having made this estimate, 
he will be required to verify its accuracy by pacing the distance. 

A few minutes each day should be spent in the practice, the 
soldier often being required to make his estimate by raising his 
rear-sight leaf and showing it to the instructor. After the first 
drills, the soldier should be required to pace the distance only 
when the estimate is unusually inaccurate. 

61. The soldier should be taught that, in judging the dis- 
tance from the enemy, his estimate may be corrected by a care- 
ful observation of the clearness with which details of dress, the 
movement of limbs, or of the files in a line may be seen. In 
order to derive the benefit of this method the soldier will be 
required to observe closely all the details noted above in single 
men or squads of men posted at varying distances, which will 
be measured and announced. 

Although the standing and kneeling silhouettes used in field 
practice afford good objects upon which to estimate distances, 



MACHINE-GUN FIRING MANUAL. 87 

the instructor should make frequent use of living figures and 
natural objects, as this is the class of targets from which the 
soldier will be compelled to estimate his mnge in active service. 

62. Methods of estimating long distances by the eye. — The 
following methods are found useful : 

(a) The soldier may decide that the object can not be more 
than a certain distance away, nor iess than a certain distance ; 
his estimate must be kept within the closest possible limits and 
the mean of the two taken as the range. 

(b) The soldier selects a point which he considers the middle 
point of the whole distance, estimates this half distance and 
doubles it, or he similarly divides the distance into a certain 
number of lengths which are familiar to him. 

(c) The soldier estimates the distance along a parallel line, 
as a road on one side, having on it well-defined objects. 

(d) The soldier takes the mean of several estimates made by 
different persons. This method is not applicable to instruction. 

63. Appearance of objects. — How modified by varying condi- 
tions of light ; difference of level, etc. During instruction the 
men should be taught the effect of varying conditions of light 
and terrain upon the apparent distance of an object. 

Objects seem nearer — 

(a) When the object is in a bright light. 
{b) When the color of the objects contrasts sharply with 
the color of the background. 

(c) When looking over water, snow, or a uniform sur- 

face like a wheat field. 

(d) When looking from a height downward. 

(e) In the clear atmosphere of high altitudes. 
Objects seem more distant — 

(a) When looking over a depression in the ground. 

(b) When there is a poor light or fog. 

(c) When only a small part of the object can be seen. 

(d) When looking from low ground upward toward 

higher ground. 



88 MACHINE-GUN FIRING MANUAL. 

64. The manner in which the subject of estimating distances 
is taught depends in a large measure upon the local facilities 
as well as upon the experience and ingenuity of the instructor. 
For this reason no course of instruction is laid down. 

The following exercises are given as a guide to instructors 
who should modify them at will to suit local conditions. 

The course of training in estimating distances is divided into 
two distinct steps or stages: 

First. Creating in the memory of the soldier an indelible pic- 
ture of the appearance of the unit of measure from every pos- 
sible viewpoint. 

Second. Giving him practice in' applying this unit of measure 
to all possible varieties of terrain and under all possible con- 
ditions of light and atmosphere. 

FIRST STAGE. 

65* First exercise. — A distance of 100 yards (the unit of 
measure) is measured accurately on level, open ground and con- 
spicuous marks are placed at each extremity of the line. It is 
explained to the soldier that this is the unit by which he is to 
estimate distances and that the attainment of proficiency de- 
pends upon his becoming familiar with the appearance of this 
unit. 

He is then required to view this distance from each extremity 
of the line, and also from different points that are neither on 
the line nor in prolongation of it. He is then required to pace 
the distance several times that he may remember the average 
number of his paces per 100 yards. 

66. Second exercise. — The unit of measure is marked as in 
the first exercise. Considering one extremity of this line (the 
extremity at which the soldier is to stand) as the center of an 
imaginary circle of 100 yards radius, stakes are placed on the 
circumference of the circle at every 30° or each hour of the 
clock. The stake "B" (pi. 49) at the further extremity of 
the unit of measure is made quite conspicuous and is considered 



MACHINE-GUN FIRING MANUAL. 89 

as being at 12 oclock. The other stakes are carefully concealed 
in such manner that their location is not apparent from the 
center stake at "A." They are referred to by the usual clock 
designation. The arrangement of the stakes is modified to suit 
the conditions imposed by whatever ground happens to be avail- 
able. 

B 
o o 

§ 

o 5 o 

§ 

I 

-E o £ o nr 

A 



Q 

"CI 

Plate 49. 

The instructor designates one or more men to assist him. 

When the stakes are in place and the men (usually not more 
than a squad at a time) are assembled at the center, the in- 
structor directs one of his assistants to stand on the line from 



90 MACHINE-GUN FIRING MANUAL. 

the center to the 1 o'clock or 11 o'clock stake and at a certain 
distance either short of or beyond the designated stake. He 
requires the men to turn their backs while the assistant is being 
posted. 

The assistant being posted, the instructor causes the men to 
face toward the 12 o'clock stake. He then directs them to 
compare the distance to the assistant with the true unit of 
measure and to decide whether the former is greater or less 
than 100 yards. 

He then calls upon one of the men to direct the assistant to 
move forward or back and halt .at a point that he, the esti- 
mator, considers is exactly 100 yards from the center stake. A 
memorandum is kept showing the assistant's actual distance 
from the center stake, and the same procedure is repeated for 
each man in the squad, when the instructor causes the assistant 
to post himself accurately at 100 yards from the center stake 
and then notifies the men of the amount and direction of their 
errors. 

Under these conditions the errors should be small, as the 
soldier constantly has before him the measured 100-yard unit, 
which is in such close proximity to the line on which he is 
estimating that comparisons are quite simple. 

As soon as the men show proficiency in this first step, the 
instructor causes the assistant to move to the 2 o'clock or 10 
o'clock stake, then to the 3 or 9 o'clock stake, etc., gradually 
working away from the visible measured unit in order to make 
comparisons more difficult. 

67. Third exercise.— This is the same as the second exercise 
except that all marks showing the location of the further end 
of the measured unit are obliterated. When practicable, this 
exercise should not be held on exactly the same ground as was 
the second. 

The basis of comparison is the man's recollection of the ap- 
pearance of the unit of measure. 



MACHINE-GUN FIRING MANUAL. 91 

68. Fourth exercise. — From practice in the foregoing exer- 
cises, the men will have become familiar with the appearance 
of the unit of measure when standing at one of its extremities. 
It next becomes necessary to familiarize them with its appear- 
ance when they are at a point in prolongation of the line and at 
various distances from its nearer extremity. 

Level open ground is used in this as in the foregoing exercises. 

Stakes are arranged as prescribed in the second exercise, ex- 
cept that they are placed on the circumferences of two con- 
centric circles (or as extensive arcs as the nature of the terrain 
will permit), one having a radius of 100 yards and the other 
a radius of 200 yards. The stakes on the smaller circumfer- 
ence or arc will be made plainly visible, those on the larger 
being carefully concealed except one which marks the further 
extremity of the unit of measure. 

The procedure in this exercise is the same as in the second 
exercise, the men being required to place the assistant at a point 
which they -consider 100 yards beyond the inner row of stakes, 
first in conjunction with a visible unit of measure and later 
basing their judgment on their recollection of its appearance. 

This exercise is repeated at such longer ranges as the terrain 
affords up to 1,000 yards. 

69. So far, all estimates have been made from the standing 
position. In combat the necessities of concealment and defilade 
will make the prone position the habitual one, hence the corre- 
sponding necessity of becoming adept at estimating distances in 
that position. 

The foregoing exercises are therefore repeated, the soldier 
making all his estimates from the prone position. 

Up to this point only open level ground has been used, this 
being the foundation or basis for all future progress in the 
estimation of distance. 

It now remains to repeat these exercises under as great a 
variety of conditions as the terrain and the climate will afford. 



92 MACHINE-GUN FIRING MANUAL. 

The soldier should be made familiar with the appearance of the 
unit of measure on bright, sunny days and on overcast days ; 
in rain, fog, or snow ; on ground that is rising, falling, even, or 
undulating; over ground that is plowed, bare, grassy, or cov- 
ered with brush; in fact, under every conceivable condition or 
combination of conditions that might surround a fire fight. 

SECOND STAGE. 

70. Up to this time it has been the endeavor to impress 
npon the soldier's memory the appearance of "the unit of meas- 
nre under all possible conditions. • 

In the second stage of instruction he is required to apply this 
knowledge in the determination of unknown distances. 

71. Fifth exercise. — The instructor selects an observation 
point from which a wide arc of vision may be had. 

He picks out some prominent landmark about 300 to 600 yards 
distant and points it out to the men, explaining that they are 
now to apply their knowledge of the appearance of the unit of 
measure in determining the range to this object. 

He further explains that in order to make this estimate it is 
necessary to recall to the memory the appearance of the unit 
of measure and to apply this unit to the ground in the same 
manner that a ruler is applied in the measurement of short 
lengths. 

He then cautions the men against the common fault of at- 
tempting to judge of the distance to an object by its appearance 
alone, although it is well, should time admit, to use the appear- 
ance of the object as a check against the unit-of -measure system. 

He further explains to the men that in the use of the unit-of- 
measure system the objective is to be considered merely as indi- 
cating the direction of the line upon which the estimate is to be 
made and as the limit to which the estimate is to extend. 

The instructor then adds such remarks as may apply to the 
special peculiarities of the ground that is to be measured and 



MACHINE-GUN FIRING MANUAL. 93 

explains that it is necessary for the soldier first to pick out 
some point in the direction of the objective that he considers 
to be 100 yards distant ; then to pick out a second point 100 
yards beyond the first ; then a third point 100 yards beyond the 
second, and so on until the objective is reached. 

The men are now directed to estimate the distance to the 
objective, to write their estimates on a piece of paper, and 
without communicating their decisions to each other to turn 
in the written estimates to the instructor. 

72. Unless the instructor has had the true ranges measured 
before the exercise begins he should adopt some speedy and 
accurate method for their determination. If the time must be 
taken to measure the true range with a chain or tape after 
each estimate, the enforced inactivity of the majority of the 
men is apt to cause their interest to lag, with the result that 
much of the instructional value of the exercise is lost. 

Speed is not sought in these first estimates. On the contrary, 
as much deliberation is allowed as may be required to insure 
results that are really estimates and not mere guesses. 

When all the men have handed in their estimates, the in- 
structor announces the true range and enters into such explana- 
tion as he may deem necessary as to the amount and direction 
of unusual errors. 

Additional objectives are then selected and the same pro- 
cedure repeated. 

When the men begin to exhibit a reasonable degree of ac- 
curacy, then speed is sought and the practice continued from 
day to day until the desired standard of proficiency is attained. 

In the selection of objectives it would be well at this stage 
of the training to include some that will resemble the targets 
that would be encountered in combat. 

73. Collective estimating. — The training of an organization 
in the estimation of distance is not complete until the leaders 
(and those individuals who, in the exigencies of the campaign, 



94 MACKINE-GTJN FIRING MANUAL. 

might be called upon to act as leaders) are able quickly to take 
advantage of the combined estimates of some or all of the 
individuals under their command. 

It is of little moment what system is used, so long as it is 
simple and uniform in the organization. 

The following system is suggested as meeting these require- 
ments : 

Let two good estimators in each squad estimate the distance 
and signal their estimates to their respective squad leaders. 
The squad leaders (mentally) average the two estimates that 
they receive and signal these averages to their respective pla- 
toon leaders. The platoon leaders (mentally) average the 
mean estimates that they receive from their squad leaders and 
then signal these averages to the company commander. The 
company commander then averages the two means that he re- 
ceives from the platoon leaders and announces the result as the 
range to be used. 

It will be noted that by the use of this system no single 
leader is called upon to obtain the mean of more than two quan- 
tities, a comparatively simple task in mental arithmetic. And 
yet, finally, the company receives the mean of many estimates 
as the range to be used. 

In the training of leaders and prospective leaders in the sub- 
ject of collective estimating, it is well to remember that it is 
the eye and not the ear that is to be trained, i. e., that the esti- 
mated ranges usually will be signaled to the leaders rather than 
communicated to them by word of mouth. 

The preliminary exercises in this subject are nothing more 
than some form of mental gymnastics. 

74. A suggested exercise. — The instructor assigns two men 
as assistants and furnishes each with a paper on which a series 
of assumed ranges are noted, thus : 



MACHINE-GUN FIRING MANUAL. 



95 



To assistant — 


No. 1. 


No. 2. 


1... 

c'.v. 




.. 600 
:.. 600 
.. 600 
.. 600 
.. 700 
.. 900 
.. 700 


1 

2 

3 




.. 800 
.. 700 
.. 400 


4 

5 




"*Etc7" 


.. 500 
.. 800 
.. 700 
.. 500 


Etc. 



The two assistants, standing about 5 or 10 yards apart, face 
the instructor at a distance of about 25 yards. The leaders 
undergoing instruction are in line at convenient intervals facing 
the assistants at a distance of about 15 yards, thus : 



Assistant 
No. 1. 



Assistant 
No. 2. 



O O 

Leaders. 



O 

Instructor. 

Plate 50. 



The instructor calls to the assistants, " Range No. 1." No. 1 
assistant would then signal " 600 " while No. 2 assistant would 
signal " 800." The leaders then determine the mean of these 



96 MACHINE-GUN FIRING MANUAL. 

two quantities and, facing about, signal their results to the in- 
structor. 

At first there should be an appreciable interval between the 
time that the range is signaled by assistant No. 1 and the time 
when it is signaled by No. 2. As progress is made, however, 
this interval of time gradually may be reduced until finally both 
assistants signal their ranges at the same time. 

In similar manner, the instructor first demands absolute 
accuracy in the announcement of the mean ranges, speed being 
sought later, but never at the expense of- accuracy. 

75. Leaders may be considered proficient in this work when, 
in the prone position, they can receive two ranges by signal, 
determine the mean accurately, and transmit that mean by 
an intelligible signal in a reasonable time. 

An organization may be considered proficient when, in the 
prone position, ranges are estimated by individuals in the firing 
line, transmitted by signal through squad and platoon leaders 
to the company commander, an accurate mean announced by 
him that shall not differ from the true range by more than 10 
per cent, sights are set according to the range announced by the 
company commander, and all this in a reasonable time. 

To carry such a system further, means could be devised to 
the end that each unit (squad and platoon) in the organization, 
should it happen to be acting alone, could use easily and 
quickly the average of the estimates of its six or eight most skill- 
ful estimators. 

Doubtless there will be occasions, in the preliminary stages of 
an attack as well as during the preparation of defensive w T orks, 
when ihere will be ample time to assemble the skillful estima- 
tors of a company and obtain the mean of their estimates with- 
out recourse to the channel of squad and platoon leaders. On 
such occasions, however, the necessity for estimating the dis- 
tance probably will be lacking, for, as a general rule, instru- 
ments will be available for this purpose. In the preparation 
of defensive works, it even would be feasible to pace or actually 



MACHINE-GUN FIRING MANUAL. 97 

to measure the distance on the ground before contact with the 
enemy had been established. 

76. (b) Taking the Range From a Map.— At the effective 
ranges of the small-arms projectiles, it will rarely be practicable 
to scale the distances directly from the map. Machine-gun 
ranges usually are so short, in comparison to the scale of such 
maps as generally would be available to the company commander 
in the field, that it is most difficult to measure them with the 
required degree of accuracy. It should be remembered also 
that the minute details of the terrain, by which the position 
of the guns and that of the enemy might be identified, will 
usually not be found on a small-scale map, while on the other 
hand, experienced troops will avoid locating themselves in the 
vicinity of prominent landmarks such as might be shown on a 
map of this character. 

In the rare instances when a company commander has a large- 
scale map available, the determination of ranges from it is 
merely a matter of reading the map. 

77. (c) Obtaining the Range From Troops Already En- 
gaged. — This is merely a matter of inquiry on the part of the 
company commander of the nearest leader whom he finds on the 
firing line. This inquiry may be verbal or by the signals pre- 
scribed in the Drill Regulations. 

78. (d) Measuring the Range Directly on the Ground. — 
The distance on the ground may be measured by — 

1. The use of a tape or chain ; 

2. The pacing of horse or man ; or 

3. The instruments of precision of the engineer. 

It is obvious that none of these methods are practicable 
except on the defensive when ample time is available before 
the possibility of contact with the enemy. 

Training in this, as in the use of maps for the determination 
of ranges, may be had in connection with the instruction in 
topography. 

106191°— 17 7 



98 MACHINE-GUN FIRING MANUAL. 

The use of the transit by organizations other than engineer 
troops would be so exceptional as to preclude the idea of instruc- 
tion in the use of this instrument in machine-gun companies. 

79. (e) Estimating Distance by Sound. — Sound travels at 
the rate of 1,100 feet, or 366 yards, per second. If a gun is fired 
at a distance, a certain time elapses before the sound is heard. 
If the number of seconds or parts of seconds between the flash 
and the report be carefully taken and multiplied by 366, the 
product will be approximately the distance in yards to the gun. 
This method will be of doubtful use on the battle field, owing 
to the difficulty of distinguishing the sound of the gun, whose 
flash is seen, from that of any other. It will probably be useful 
in determining the range to a hostile battery when it first opens 
fire. 

80. (/) Range Finders,— Training in the use of range-find- 
ing instruments will depend upon the type of instrument that is 
supplied to the organizations. (See par. 54.) 

81. Range Estimators. — The instruction in estimating dis- 
tance having been completed, five or six enlisted men, selected 
by the company commander from the most accurate estimators, 
will be designated as " range estimators." These men will be 
given practice in estimating distances throughout the year. The 
practice will be on varied ground and at distances up to 2,000 
yards. 



CHAPTER VI. 
RECOGNITION AND DESIGNATION OF SERVICE TARGETS. 

RECOGNITION of targets. 

82. Scouts or patrols preceding the guns when going into 
action, or those providing for the security of the guns on the 
march or in action, must be able quickly to see, recognize, and 
distinguish between hostile and friendly troops, and must also 
be able to locate objects of a military nature or significance 
within range of their vision. 



MACHINE-GUN FIRING MANUAL. 99 

Circumstances may demand that machine guns be held in 
positions of concealment, while but one or two scouts are kept 
on the outlook. These scouts must also be trained in the recog- 
nition of objectives. 

It is also important that the men using the gun be able to 
locate quickly and recognize targets whose whereabouts is de- 
scribed to them briefly, but whose outlines are obscure and 
blend with the surrounding country. 

Ability to observe an object depends on two qualifications of 
the individual : 

First, his acuity of vision, which is constant for the individual 
and not susceptible of improvement by training. 

Second, his power or faculty of perception. This power of 
perception can be increased by training. 

Training in recognition of targets should, therefore, be de- 
signed with a view to increasing the powers of perception. 

When the recruit first enters the military service objects of 
a military nature or significance are unfamiliar to him. It is 
necessary, therefore, that he be taught, first, what to look for, 
and then how to look for it. 

EXERCISES IN RECOGNITION OF TARGETS. 

83. First exercise. — It is the purpose of this exercise to 
teach the recruit what to look for and to demonstrate to him 
how quickly the eye is attracted by movement. 

It is explained that, in combat, the enemy will use every en- 
deavor to obtain concealment, and when seen at all, usually will 
be in the prone position. Perhaps it will occur that only the 
head and shoulders are seen above the parapet of a trench, or 
parts of the head and shoulder will appear from behind a tree 
or wall. 

The instructor then conducts the men to the point selected 
for the exercise. This point should admit of a wide arc of 
vision and should permit of an uninterrupted view for a dis- 
tance of from 100 to 200 yards. 



100 MACHINE-GUN FIRING MANUAL. 

Several assistants are posted beforehand at various short 
ranges and in various directions from the central point. They 
make use of no cover, but are in the prone position and are re- 
quired to remain quite immobile or at least to make no con- 
spicuous movements. 

The instructor informs the men that one of his assistants is 

lying prone at a distance of less than yards, that he is 

in the open and in the general direction of (indicating 

by pointing the general direction of the first objective). He 
then directs them to look the ground over carefully and attempt 
to locate this man, and then calls them up in turn and causes 
them to point out his position. For this purpose, a rifle with 
sandbag and tripod may be used to advantage, or else a ma- 
chine gun on a tripod mount, the recruit being required to 
sight the rifle or gun at what he believes to be the objective. 

Should any of the men fail to locate the objective, the in- 
structor signals to the assistant to raise his arm or to move 
from side to side. A very slight movement usually will betray 
his position. 

This is repeated until all the objectives have been located. 

84.- Second exercise. — The purpose of this exercise, like the 
first, is to familiarize the men with the appearance of various 
forms of objectives. 

The procedure is the same as in the first exercise, except that 
the assistants are concealed very slightly at first, the amount 
of concealment being increased as progress is made. 

85. Third exercise. — The purpose of this exercise and the 
procedure is the same as the foregoing. 

The assistants, however, are placed in groups of two or more 
men per group. The number of assistants per group, the range, 
and the amount of concealment are gradually increased. 

In addition to locating the objectives, the men are required 
to state the number of figures in each group and to add any 
further details, such as peculiarities of dress or position, as the 
instructor may require. 



MACHINE-GUN FIEING MANUAL. 101 

86. Fourth exercise. — It is the purpose of this exercise to 
teach the men an effective method of searching a given area. 

To search a given area thoroughly, the man's sight must not 
be permitted to wander aimlessly, but must be directed in such 
manner that every portion of the area is subjected to rigid 
scrutiny. To meet this demand, a system is necessary that will 
assure that no portion of the area is overlooked or slighted. 

There are two systems or methods in general use and which 
have been found to give satisfactory results. 

Both systems subdivide the area by a number of imaginary 
lines, in one case these lines being at right angles to the line 
of sight and in the other case being parallel to it. The di- 
vision by lines parallel to the line of sight usually will be pro- 
ductive of the better results. 

It should be explained to the recruit that it is of no special 
importance what system is used, but that it is important that 
some system be used that will give the 'required results. 

Having completed the explanation of the exercises the in- 
structor indicates certain boundaries in which various objec- 
tives of a military nature have been placed beforehand and 
directs the men to search this area and to describe all such 
objectives as they are able to locate. 

As progress is made the area, the amount of cover used, the 
size and number of the objectives, and the ranges are gradually 
increased. 

As a check on the men's imaginations the instructor occa- 
sionally should designate an area in which no objectives have 
been placed. 

87. Up to this point only natural cover has been considered. 
It is also important for the soldier to become familiar with 
natural and cultural features and to note the changes that 
occur when these same objects have been adapted to military 
uses. 

Usually a saving in time may be effected by having this prac- 
tice in conjunction with that in field engineering. 



102 MACHINE-GUN FIRING MANUAL. 

In all this practice the men should be impressed with the 
difference between mere concealment and concealment of loca- 
tion and should be taught that the latter is always to be sought. 

Exercise might consist of having the gun squads prepare 
various positions for defense and then have each squad at- 
tempt to locate the positions of the others from such points as 
they naturally would be viewed by the enemy. 

It should be borne in mind, however, that in combat the usual 
target for machine guns will be the hostile infantry, and hence 
the bulk of this practice should be with a view to familiarizing 
all with the appearance of the various devices used by the in- 
fantry to secure concealment or defilade or both. 

88. In all of these exercises the men are first permitted to 
search for objectives from the easiest vantage points, standing 
in full view in the open should they so desire. As proficiency is 
attained, however, the instructor demands a closer adherence 
to combat conditions, with the ultimate intention of having the 
search made in the prone position and from such cover as may 
be available. 

TAEGET DESIGNATION. 

89. Within the company implies an ability on the part of 
the company commander to describe the objective or fronts for 
his platoons within the limits assigned to the company. It also 
implies an ability to cover the whole target of the company 
during a forward movement of part of the company. 

Within the platoon implies an ability on the part of the pla- 
toon leaders to understand the company commander's designa- 
tion of the target and to transmit that information to their 
platoons in such a manner as to insure an equal distribution of 
their fire within the front assigned them as objectives, not 
slighting the less visible parts. 

In general, targets with reference to their designation will 
fall under the following heads : 



. MACHINE-GUN FIRING MANUAL. 103 

(1) Those that stand out so plainly that the target is obvious. 

(2) Those targets that are plainly visible but about which 
there might be some confusion. 

(3) Those targets which are partially visible but which on ac- 
count of backgrounds or other conditions are difficult to pick up. 

(4) Those targets which can be seen only with field glasses. 
90. Methods of Designation. — In the first case it is a 

simple matter, as follows : 

System. Example. 

1. Announce range. ** Range 1.000." 

2. If sights are to be set, al- 

low time necessary. 

3. Announce objective. "A troop of cavalry." 

The distribution and width of the target are taken up later. 

In the designation and description of the target it is essential 
that a system of angular measurement be adopted and that all 
be instructed in its use. The angular unit that has been adopted 
for this purpose is the mil. ( See par. 55. ) 

In the second case the horizontal clock system may be used 
(with visible targets). 

To avoid confusion it is necessary when using a clock system 
to preface the direction with the words, "Reference point" or 
" Target." 

System. Example. 

1. 'Announce range. " Range 1,000." 

If sights are to be set, 
allow time necessary. 

2. Announce direction. " Target at 2 o'clock." 

3. Announce objective. "A troop of cavalry dis- 

mounted. 

PROCEDURE. 

1. Gunners set sight at 1,000 yards. 

2. All look along a line pointing toward 2 o'clock of a hori- 
zontal clock face whose center is at the firing point and the 



104 



MACHINE-GUN FIRING MANUAL. 



direction of whose 12 o'clock mark is perpendicular to the firing 
line. 

3. Look for objective at 1,000 yards on this 2 o'clock line. 

91. In the third case the vertical clock system is used either 
singly or in combination with the horizontal (against small or 
indistinct targets). 



System. 

1. Announce range. 

If sights are to be set, 
allow time necessary. 

2. Announce the general direc- 

tion of the reference point. 

3. Designate as a reference 

point the most prominent 
object in the zone indi- 
cated. 

4. Announce the position of the 

target with respect to the 
reference point. 

5. Announce objective. 



Ran; 



Example, 
re 1,000." 



1 Reference point to our right 
front "(or "at 2 o'clock"). 

'A stone house with two 
chimneys." 



; Target at 3 o'clock.' 



"A hostile patrol of four men." 



PROCEDURE. 



1. Gunners set sight at 1,000 yards. 

2. All men look to their right front (or along the 2 o'clock 
line horizontal clock). 

3. The reference point (stone house) is found in the indicated 
direction. 

4. A clock face (vertical) is imagined centered on the refer- 
ence point, and the men look along the line leading from the 
clock center through 3 o'clock and 

5. Find hostile patrol at 1,000 yards from the firing point. 

It will often be necessary to use the mil scale, the rear sight 
or fingers to lay off the distance to the target from the reference 



MACHINE-GUN FIRING MANUAL. 105 

point and at the same time to indicate its lateral width and its 
subdivision into parts. 

The term " one finger " is taken to mean 50 mils. 

92. Care must be taken to distinguish between the enemy's 
right and our right. Such terms as " enemy right," " right of 
enemy's line " must be used when referring to the enemy and 
" our right " ; " right of our line " when referring to our forces, 
and the terms must never be confused. 

Reference points are not used when the target is plain and 
of such a nature as to be easily pointed out. 

Orders should be as short as possible without losing in clear- 
ness. Hence to use a reference point when not called for is to 
add more to the order than necessary. 

Reference points chosen should be definite and easily dis- 
tinguished. 

Data given from reference points must be complete. 

The distance from the reference point to the right, left, or 
center of the enemy's line should be stated, as well as the width 
of the target that it is intended to cover. Do not sacrifice 
clearness to brevity. 

93. The mil system may be used in switching targets. If, 
for instance, it is desired to change laterally to a new target, 
the prescribed signal for switching fire is made, " two fingers 
to the right," for example, and each gunner then changes his 
fire the designated distance to the right as has been signaled. 
The front covered by the fire of the unit remains the same 
width, but the center of the sheaf has been moved 100 mils 
to the right. 

The designation of an aiming point is the same as the desig- 
nation of a target of the visible class. 

Precautions must be taken to prevent the gunner being con- 
fused by the difference between the actual range to the target 
and the sight setting announced in the fire order. 

By dividing a given target, frontage, area, or sector into 
fractional parts and by assigning to each subdivision of his 



106 MACHINE-GUN FIRING MANUAL. 

unit one or more of these parts a commander is able to secure 
a proper distribution of fire. A correct application of the 
principles of target designation is the means employed to secure 
this distribution. It is unusual to assign less than two guns 
to any given sector or objective. 



CHAPTER VII. 
KNOWN DISTANCE PRACTICE. 

GENEKAL. 

94. Definition. — Known distance practice consists of firing 
ball cartridges at machine-gun targets JMGA, MGB, MGC, and 
MGD at a distance of 27J- yards. 

95. The object of known distance practice is to give the 
soldier prior to combat firing a certain amount of training 
with service ammunition against targets of such a nature that 
his errors may be readily detected and pointed out to him. It 
should be kept constantly in mind that the final measure of fire 
in batttle is the number of enemies disabled in a unit of time, 
and every effort should be directed toward bringing the soldier's 
marksmanship up to a high state of proficiency as measured by 
this standard. 

96. General.— -1. The soldier is practiced in reloading, both 
when the new strip or belt is placed in the gun or the magazine 
is placed on the gun (Lewis), by his assistant, and when the 
reloading is done by the firer. By this practice any derange- 
ment of the aim caused by the operation of loading should be 
overcome. 

2. The soldier is then taught to " hold," i. e., when directing 
his fire at a single aiming point to confine the resulting shot 
group within limits found by experiment to be possible for men 
well trained in the use of the machine gun. 



MACHINE-GUN FIRING MANUAL. 107 

3. He is next taught the principles of and given practice 
in " fixed fire." Fixed fire is that fire directed at an objective 
of such size that it may be covered effectively by a single cone, 
i. e., a single aiming point is used. By this practice the soldier 
is taught to place the center of impact of his shot group at 
the center of the target. 

4. The fourth step in known distance practice consists in 
teaching the soldier the principles of and giving him practice 
in firing at objectives of such size and shape that the fire must 
be distributed laterally, in depth, or in combination of these 
methods, in order that an even distribution of impact may be 
obtained throughout the entire area. 

97. Individual, — The general scheme for firing is as follows: 

fl. Reloading on target MGA. 

2. Holding on target MGA. 

1 3. Fixed fixe on target MGA. 

fTnstrnrtion r>raotiopsi 4 * distributed fire on target MGB. 
instruction practice^ 5> Searching fire on target MGB> 

Known I 6. Searching with distribution on target MGB . 

distance.] 7. Searching with distribution on target MGC. 

8. Searching with distribution on target MGD. 
(.Record. 1. Searching with distribution on target MGD. 

INSTRUCTION PRACTICE. 

98. Reloading.— (Target MGA.) Proficiency having been 
acquired in the details involved in the process of reloading, a 
strip, belt, or magazine, containing two cartridges in the last 
spaces, is placed in the gun. Aim is carefully directed at a 
designated aiming point, the two shots fired and another car- 
tridge container containing two cartridges in the first spaces 
loaded and fired without unnecessary delay. 

The positions of the hits on the target will indicate the extent 
the soldier's aim and position has been aifected by the opera- 
tion of reloading. 



108 MACHINE-GUN FIRING MANUAL. 

This exercise will be held — 

First. With loading done by an assistant. 
Second. With loading clone by firer. 

The interval between firings should not exceed five seconds 
when loading without assistance and three seconds when an 
assistant loads. 

99. Holding. — (Target MGA.) The practice in holding is a 
verification, with ball cartridges, of the soldier's ability to take 
the firing position properly and to maintain it with uniformity 
while firing. 

The soldier being in the firing position, the piece loaded, the 
instructor directs the soldier to fire a string of five shots at a 
designated aiming point. To avoid a waste of ammunition at 
the beginning of the practice, the instructor directs that every 
sixth cartridge space be empty. 

The soldier having fired his string of five shots, the target 
is drawn back to the firing point, and the shot group is examined. 
The entire group (exclusive of "strays") should be contained 
within the circumference of an ellipse with a horizontal diam- 
eter of S.5 inches and a vertical diameter, of 2.5 inches. With 
the tripod mount the shape of the group is modified somewhat — 
the vertical diameter of the ellipse is the same but the horizontal 
diameter is 2 inches. 

A convenient gauge for this purpose is made by bending a piece 
of wire in the shape of the ellipse and twisting the ends together 
to form a handle. By applying this wire ring to the face of the 
target, it can be determined at a glance whether or not the shot 
group is within the required limits. 

Should the soldier's first group of five .shots not be within the 
gauge, he is required to repeat the practice, the instructor observ- 
ing carefully for faults in his position and instructing the soldier 
how to correct those faults. 

A satisfactory group of five shots having been made, the 
soldier is next required to fire two strings (of five shots each) 
in succession. All 10 shots must now be grouped within the 



MACHINE-GUN FIRING MANUAL. 

SHOT GROUP GAUGES 



109 




Plate No. 51. 



110 MACHINE-GUN FIRING MANUAL. 

gauge. The instructor observes the firer, notes and corrects 
faults as before. As progress is made, the soldier is required 
to fire three, four, and finally five strings (of five shots each) 
in succession and to place all the shots of the combined group 
in each case within the limits marked by the gauge. 

The soldier is next required to fire two strings of 15 shots 
each and finally a string of 30 shots. The groups must lie 
within the gauge as before. 

A too rigid insistence on the entire group being within the 
limits of the gauge is not desirable. A well-trained instructor 
will know when wide shots are due to faulty holding and when 
they are merely strays. 

When the groups show by their size that the soldier's fire is 
becoming dependable, he should keep a record of the center of 
impact of each group that he fires. This record should show the 
sight setting used, the theoretical height of the center of impact 
above the point of aim for that particular sight setting, the actual 
distance of the center of impact above the point of aim, and the 
difference between the actual and theoretical ordinates expressed 
in mils. The mean of all these differences will give the soldier 
a fairly good idea of what his " equation " is with that particular 
gun and should remain quite constant for all ranges. 

100. A convenient scale to use for the purpose indicated in 
the preceding paragraph is shown in plate 52. On this scale 1 
mil intercept is equal to 1 inch, and the ordinates in inches 
from the lower end of the scale are given in paragraph 102 for 
United States Ammunition and for British Mark VII Ammu- 
nition. 

The position of the zero on the scale is determined as follows : 
To the height in inches of the front sight above the axis of the 
bore add the distance in inches that the bullet falls vertically 
between muzzle and target. These values for drop of bullet are 
0.173 inch for United States ammunition and 0.226 inch for 
British Mark VII ammunition. Then add 0.8 inch for jump of 



MACHINE-GUN FIRING MANUAL. Ill 

the gun. The position of the zero for various guns is given in 
paragraph 103. 

From this firing and the use of the scale in connection with it 
the soldier should learn exactly what sight setting to use on that 
particular gun in order that the center of impact will lie on a 
given ordinate. When he has this data he will be able, by use 
of the same sight settings, to place his cone of fire exactly at 
any ordered range when he comes to field firing, providing the 
muzzle velocity of the gun remains constant. Data for each 
barrel for each gun showing the elevation required on the sight 
in order to hit the 500-yard ordinate when the aiming point 
appropriate to the type of gun is used must be carefully pre- 
served in the organization for use in connection with technique 
of fire. 

101. To obtain this data concerning the 500-yard ordinate 
the following system may be used in connection with the work of 
instruction under this paragraph. 

Paste an aiming point 1 inch high and 10 inches long at some 
convenient point on the target. Aim will be taken at the bottom 
edge of this aiming point. The sight should be raised or lowered 
after each trial firing until the center of impact for groups of 
three or more shots is as shown in the following table : 

Lewis gun, center of impact 0.9 inch above bottom of A. P. 

Benet-Merci§ rifle, center of impact 2.1 inch above bottom of 
A. P. 

Vickers gun, center of impact on bottom edge of A. P. 

Maxim gun, center of impact 0.3 of an inch below bottom of 
A. P. 

Make a record of the sight setting required to get this effect. 
If several men fire the same gun, each man should get this data 
for the barrel that he uses, and the mean of their results should 
be the sight setting recorded for that barrel of that gun. 



112 MACHINE-GUN FIRING MANUAL. 

102. Ordinates at 27^ yards. 



N^. 



Yards. 


United 
States 
ammu- 
nition. 


British 
Model 
VII. 




Inches. 


Inches. 


100 


0.547 


0.000 


200 


1.357 


.789 


300 


2.197 


1.699 


400 


3.267 


2.917 


500 


4. 497 


4.338 


600 


5.817 


6.000 


700 


7.457 


7.972 


800 


9.257 


10.244 


900 


11. 357 


12. 893 


1,000 


13. 877 


15.949 


1,100 


16. 637 


19.449 


1,200 


19. 737 


23.402 


1,300 


23.157 


27.879 


1,400 


26. 917 


32. 716 


1,500 


30. 907 


38. 571 


1,600 


35. 337 


44.894 



103. Position of zero on scale. 



Gun. 


Inches 
from 
lower 
end of 
scale. 


Maxim 

Vickers 


4.83 
4.50 


Benet-Mercie 

Lewis 


2.40 
3.40 



MACHINE-GUI* FIRING MANUAL. 113 

104. Fixed Fike. — (Target MGA.) The purpose of this prac- 
tice is to insure such a precise knowledge of the gun on the part 
of the soldier that when the instructor orders firing with 
"Range 400 (or so many) yards," said firing will result in the 
production of a cone whose mean trajectory is 400 (or so many) 
yards. 

As the essence of this practice is a knowledge of the amount 
of change in sight reading from the normal and of how to apply 
this change in actually setting the sight, it is obvious that much 
of the practice may be confined to work in merely setting the 
sight, the firing of ball cartridges being limited to a few groups 
for the purpose of verifying or demonstrating the correctness or 
incorrectness of the soldier's work. 

105. Distributed Fire. — (Target MGB.) The object of this 
practice is to secure an even distribution of fire throughout the 
entire width of a linear target. 

Except that ball cartridges are used, the practice is similar 
to that given in paragraph 44. 

At first the soldier fires but a single shot at each aiming point, 
and not more than about 10 aiming points are used. The result- 
ing shot group should show a distribution that would approxi- 
mate one hit to each 3 inches of front covered on the target, 
and no shot should be more than about 2 inches above or below 
the space containing the center of impact. 

By totaling and recording the number of hits in each hori- 
zontal and in each vertical ruled space on the target, the 
instructor may readily determine whether the distribution is 
even and whether or not the center of impact is at the correct 
height. 

The soldier will next distribute his hits at intervals of about 
2^ mils by utilizing the means determined in preliminary 
training. 

When proficiency in the even distribution of single shots has 
been attained, the soldier will fire strings of about three shots 
at each of 10 aiming points. In this practice 30 shots will be 
fired in short bursts at a front represented by 10 targets. 
106191°— 17 8 



114 MACHINE-GUN FIRING MANUAL. 

Finally the feature of reloading is introduced and it is sought 
to develop a rate of fire that shall not fall below 150 shots per 
minute, including reloading. 

The vertical distribution of the shot group, in the various 
horizontal ruled spaces on the target above and below the 
center of impact, should show an average percentage of hits 
approximately as follows : 

Per cent. 

Fourth space above the center of impact 2 

Third space above the center of impact 5 

Second space above the center of impact 12 

First space above the center of impact 18 

Space containing the center of impact 26 

First space below the center of impact- 18 

Second space below the center of impact 12 

Third space below the center of impact 5 

Fourth space below the center of impact 2 

The soldier's progress is considered satisfactory when, with 
five shots per aiming point, he can strike 60 per cent of the 
rectangles in the horizontal space in which the center of impact 
should be placed. 

106. Searching Fire.— ( Target MGB.) The object of this 
firing is to give the soldier practice in securing an even distribu- 
tion of fire in the direction of depth and in certain specified 
amounts. 

The general method of executing searching fire conforms to 
that for the execution of distributed fire. The aiming points 
are placed at vertical intervals of 2 mils and aim is taken at 
each aiming point in turn, beginning at the top or bottom one 
as the instructor may direct. 

The soldier at first fires but one shot at each aiming point, 
and not more than about 10 aiming points are used. The 
resultant shot group should be contained in a rectangle about 
2\ inches wide and about 2 inches longer than the line of 
aiming points. 

The soldier will next attempt to distribute his hits in a verti- 
cal line, starting up or down from a single aiming point, so 
that the single shots will be placed with a vertical interval of 



MACHINE-GUN FIRING MANUAL. 115 

about 2 mils. The elevating mechanism in guns so equipped 
will be used for obtaining this vertical interval. 

When the soldier can place single shots at the searching 
interval of 2 mils, he will fire bursts of about three shots 
with the 2-mil vertical interval between bursts. The instructor 
orders, " Search down (or Search up) so many mils from such 
aiming point," giving at the same time the amount per burst. 

Finally, the feature of reloading is introduced, and it is 
sought to develop a rate of fire of at least 150, including 
reloading. 

The study of the shot group by the instructor follows the 
lines set forth in the preceding paragraph. 

107. Searching with Distribution. — (Targets MGB and 
MGC. ) Target MGB : This firing is merely distributed fire, 
in which the firing at each aiming point is a searching by a 
given number of mils. 

Target MGC : This target is designed to represent a column 
marching on a hillside. The firing may be under the assump- 
tion that the range is known exactly and that the head of the 
column is 600 yards distant and the tail 700 yards distant. 
The gunner makes allowance for the difference in range there- 
for, and the center of impact of the resulting group should 
be about 3 inches above the point of aim at the head of the 
column and about A\ inches above the point of aim at the tail 
of the column. 

The practice is varied by considering that the range has been 
estimated with a probable error of a certain percentage and 
searching fire ordered in addition to the allowance for difference 
in range. 

108. Preliminary Practice on Target MGD. — Target MGD 
is the record target. The preliminary practice on this target will 
consist of one firing under the conditions of " Record practice " 
as laid down in paragraph 110, except* that the soldier may call 
" Time out " at any time and verify the results of his firing. 
Ample use of this opportunity should be made so that the sol- 
dier may be certain that his sight elevations are such that his 



116 



MACHINE-GUN FIRING MANUAL. 



shot groups are hitting the scoring spaces. The " time out " will 
be determined by the announcement " Ready " by the firer. 

Table of sight settings to be used ivith target MGD. 



Gun. 


Group 1. 


Group 2. 


Group 3. 


Group 4. 


Maxim 


700 
675 
525 
600 


575 
550 

400 
500 


1050 
1050 
975 
925 


800 


Vickers 




Benet 


675 


Lewis 


700 







Aim is taken at bottom edge of aiming points. These values 
will vary slightly for individual guns. The foregoing table is 
calculated to bring the centers of impact in centers of scoring 
spaces. 

109. Immediately after the conclusion of known distance 
instruction practice the soldier will fire the known distance 
record test. 

The two courses will not be fired by one man on the same day. 



CHAPTER VIII. 

RECORD PRACTICE. 

110. The qualification course on the known distance range 
will consist cf one firing (300 rounds) under the following rules 
and conditions : 

1. Range. — 27 J yards (1,000 inches). 

2. Target.— MGD. 

3. Firing. — As demanded by objective. 

4. Ammunition. — 300 cartridges per man. This to be loaded, 
by the individual who is to fire it, in strips, belts, or magazines 
according to the type of gun used. 



MACHINE-GUN FIRING MANUAL. 117 

5. Mount. — The mount issued as the regular equipment will 
be used. 

6. Equipment. — The firer will be equipped with a gunner's 
pouch, tool box, or other accessories necessary to the operation 
of the gun. 

7. Sight. — The leaf sight will be used and will be set at the 
appropriate elevation. 

8. All firing will be " automatic." 

9. Time. — The soldier will be allowed a minimum of two 
minutes and a maximum of seven and one-half minutes for fir- 
ing the 300 rounds, exclusive of time taken, out for jams. Time 
will be kept at the firing point by two timekeepers with stop 
watches, and the mean of the time of the two watches will con- 
stitute the time of firing. The time will commence at the firing 
of the first shot and end at the firing of the three hundredth 
shot. The soldier should study carefully the method of obtain- 
ing the percentage for classification, and base his firing method 
on the general principle of attaining the highest possible rate 
of fire consistent with accuracy. 

10. Loading. — During firing, by an assistant. 

11. Jams. — When jams occur time is taken out until the gun 
has been made to function. The candidate is then allowed to 
continue the firing in the time remaining to his credit. 

12. Score. — The score is the total number of points made by 
the firer in a given time. 

240S 
The percentage for rating is obtained by the formula T 

where S is the number of scoring spaces struck and T is the 
time in seconds required for the firing. 

13. Procedure. — The firer being in the firing position with the 
gun loaded, set at automatic, aimed, and having signified his 
readiness to fire, the command is given " Fire at will." The 
firer will determine for himself the order of firing at the different 
aiming points and the number of shots to be directed at each. 
Fire will cease at the whistle signal. The firing and scoring 
will be done under the direct personal supervision of a commis- 



118 MACHINE-GUN FIRING MANUAL. 

sioned officer, and the scores will be kept in his personal posses- 
sion until made of final record. 

14. Reports and records. — See paragraphs 131, 289, and 291. 



CHAPTER IX. 
DETERMINATION OF SIGHT SETTING. 

111. The firing at the short-range targets gives the zero of 
each .gun under the assumption that the muzzle velocity of the 
bullets fired from the gun is that for which the table of ordinates 
was calculated. But this may not be true for a comparatively 
new barrel and certainly will not be true for a badly worn 
barrel. 

In order to determine the true sight settings to be used in 
actual field firing, the following test will take place immediately 
after the known distance record practice (par. 110). 

Range, 500 yards, target " B." Choose a day when shooting 
conditions are satisfactory. Provide about 30 rounds of service 
ammunition per barrel to be tested. Fire single shots with the 
gun, changing the sight setting and windage until three shots 
in succession are in the bull's-eye. Then fire two bursts Of about 
3 shots each and note their position with reference to the bull's- 
eye. Bursts are usually higher than single shots. If the esti- 
mated centers of impact of the bursts are low or high, change 
sight setting and repeat until the center of impact is about at 
the height of the bull's-eye. If ammunition is available, verify 
by a burst of 10 shots. 

Note that both the horizontal and vertical dispersion for ma- 
chine guns at 500 yards varies from 5 to 10 feet and that all 10 
of a burst of 10 shots may not hit the 6 by 6 feet target. This 
is immaterial so long as the general shape and position of the 
group is such that the center of impact may be assumed to be 
at the approximate height of the center of the target. 



MACHINE-GUN FXKING MANUAL. 



119 



A comparison of the sight setting actually used to hit a target 
500 yards distant and the sight setting used to hit the 500- 
yard trajectory at a range of 27 yards (par. 102), gives the 
correct sight setting to be applied to this particular barrel for 
actual field firing at any range. For this purpose, refer to the 
table " Sight setting, United States ammunition" (par. 112). 

112. Table of sight settings, United States ammunition. 

[Range in yards. j 



300. 



400. 



500. 



600. 



700. 



I 
100 200 300 400 500 600 700 800 900 1,0001,1001,2001,300 



100 

100 
125 
150 
175 
200 

250 
275 
300 
325 
350 

400 
425 
450 
475 
500 



100 

100 
125 
150 
175 
200 

200 
225 
250 
275 
300 

350 
375 
400 
425 
450 

500 
525 
550 
560 
575 



100 
150 
200 
225 
250 

200 
250 
300 
325 
350 

300 
325 
350 
400 
450 

400 
450 
500 
525 
550 

550 
575 
600 
625 
650 



200 
250 
300 
350 
400 

300 
350 
400 
450 

500 

400 
450 
500 
550 
600 

500 
550 
600 
640 
675 

625 
660 
700 
740 

775 



300 
375 
450 
510 
575 

400 
460 
525 
575 
625 

500 
550 
600 
650 
700 

600 

650 
700 
740 

775 

700 
750 

800 

825 
850 



450 
500 
575 
640 
700 

525 
585 
650 
710 

775 

600 
650 
700 
750 
800 

700 
750 
800 

840 

875 

775 
810 
850 
900 



550 
625 
700 
760 
825 



650 
710 

775 



700 
775 
825 
875 
925 



9001,025 

975 1, 100 

925 1,0501,175 

9851,1101,225 

1,0501,1751,275 



750 
810 
§7", 
825| 940 
8751,000 



700 
750 

800 
850 
900 



775 
815 
850 
910 



8501 

900 

960 

,025 



850 950 

9101,025 

9751,100 

1,040,1,150 

1,1001,200 

I 

9001,000 

960,1,060 

1,0251,125 

1,075; 1,180, 

1,1251,250 



1, 140 1 
1,210 1 
1,2801 
1,3401 
1,390,1 



950 

• 1,010 

11,075 

1 1, 125 

97511,0751,175 



850 

9001 

9501 

1,0101 



850 9501,025 

9001,0001,075 

950,1,0501,125 

1,0001,1001,175 

9501,0501,150 1,225 



1,050 
1,100 
1,150 
1,210 
1,275 

1,125 
1,175 
1,225 
1, 275 
1,325 



1,0751, 
1, 140 1, 
1,2001, 
1,250 1, 
1,3001, 

I 
1, 100 1 
1,1601, 
1,2251, 
1,2801, 
1,3501, 



1751 
2401 
3001 
3501 
4101 

2001 
2701 
3301 
3901 
4501 



1,1501,2401 
1,2101,3001 
1,2751,3601 
1,3251,4201 
1,3751,4751 

1,2001,2901 
1,2601,3501 
1,3251,410,1 
1,3751,4601 
1,4251,5101 



240 
310 
380 
440 
490 

275 
340 
400 
450 
510 

300 
370 
430 
490 
550 

340 
400 
460 
520 
575 

390 
450 
500 
560 
610 



120 MACHINE-GUN FIRING MANUAL. 

112. Table of sight settings, United States ammunition — Contd. 

[Range in yards.] 





1,400 


1,500 


1,600 


1,700 


1,800 


1,900 


2,000 


2,100 


2,200 


2,300 


2,400 


2,500 




f 1,350 


1,450 


1,550 


1,650 


1,760 


1,860 


1,960 


2,060 


2,160 


2,260 


2,370 


2,475 




1,410 


1,520 


1,625 


1,725 


1,835 


1,935 


2,035 


2,135 


2,235 


2,335 


2,440 


2,540 


300... 


{1,480 


1,590 


1,700 


1,800 


1,910 


2,010 


2,110 


2,210 


2,310 


2,410 


2,510 


2,610 




1,540 


1,650 


1,760 


1,870 


1,970 


2,080 


2,180 


2,280 


2,385 


2,585 


2,600 


2,700 




[1,600 


1,720 


1,830 


1,940 


2,040 


2,150 


2,250 


2,350 


2,460 


2,675 


2,690 


2,800 




fl, 375 


1,475 


1,575 


1,675 


1,775 


1,880 


1,980 


2,080 


2,180 


2,280 


2,380 


2,485 




1,440 


1,545 


1,645 


1,750 


1,850 


1,955 


2,055 


2,155 


2,255 


2,355 


2,455 


2,555 


400... 


{ 1,500 


1,610 


1,720 


1,820 


1,925 


2,030 


2,130 


2,230 


2,330 


2,430 2,530 


2,630 




1,560 


1,680 


1,780| 1,890 


1,990 


2,100 


2,200 


2,300 


2,410 


2,510 


2,620 


2,720 




U,625 


1,750 


1,850 


1,960 


2,060 


2,160 


2,260 


2,360 


2,475 


2,590 


2,700 


2,810 




fl,400 


1,500 


1,600 


1,700 


1,800 


1,900 


2,000 


2,100 


2,200 


2,300 


2,400 


2,500 




1,470 


1,570 


1, 670 


1,770 


1,875 


1,975 


2,075 


2,175 


2,275 


2,375 


2,475 


.2,575 


500... 


a, 530 


1,640 


1,740! 1,840 


1,950 


2,050 


2,150 


2,250 


2,350 


2,450 


2,550 


2,650 




1,590 


1,700 


1,810 1,910 


2,010 


2,110 


2,210 


2,320 


2,425 


2,530 


2,635 


2,740 




[1, 650 


1,760 


1,875 1,980 


2,080 


2,180 


2,280 


2,390 


2,500 


2,610 


2,720 


2,825 




f 1, 430 


1,530 


1,630 


1,730 


1,830 


1,925 


2,020 


2,120 


2,220 


2,320 


2,420 


2,515 




1,500 


1,600 


1,710 


1, 810 


1,910 


2,000 


2,095 


2,195 


2,295 


2,395 


2,490 


2,590 


600... 


n,560 


1,660 


1,775 


1,875 


1,975 


2,070 


2,170 


2,270 


2,370 


2,470 


2,560 


2,660 




1,620 


1,725 


1,830 


1,930 


2,030 


2,135 


2,235 


2,335 


2,440 


2,545 


2,645 


2,750 




U;675 


1,790 


1,900 


2,000 


2,100 


2,200 


2,300 


2,400 


2,510 


2,620 


2,730 


2,840 




f 1,475 


1,575 


1,660 


1,760 


1,860 


1,960 


2,050 


2,150 


2,240 


2,340 


2,430 


2,525 




1,540 


1,630 


1,730 


1,830 


1,930 


2,030 


2,120 2,220 


2,315 


2,415 


2,505 


2,600 


700... 


{ 1,600 


1,700 


1,800 


1,900 


2,0r>0 


2,100 


2,190 2,290 


2,390 


2,490 


2,580 


2,680 




1,660 


1,760 


1,860 


1,960 


2,0*0 


2,160 


2,260 


2,360 


2,460 


2,560 


2,660 


2,765 




U,710 


1,825 


1,925 


2,025 


2,125 


2,225 


2,325 


2,425 


2,530 


2,630 


2,740 


2,850 



113. The numbers 300, 400, 500, 600, and 700 at the left 
indicate the sight elevations used in order to get the center of 
impact on the 500-yard trajectory of the short-range target. 
The five lines of sight settings following each of the above 
numbers are for trajectories with muzzle velocities varying 
from 2 J00 f. s. to 2,300 f. s. 



MACHINE-GUN FIRING MANUAL. 121 

An example will show how to use this table. A certain barrel 
required a sight setting of 600 yards at the short range to get 
the center of impact on the 500-yard ordinate of the short-range 
target. An elevation of 650 yards had to* be used at the 500- 
yard range in order to get the center of impact on the bull's-eye 
of the " B " target. 

Consult the table with the number 600 at the left and in the 
column headed " Range in yards 500 " find the number 650. 
This is in the second line of the 600 group. This second line 
beginning 275 and ending 2,590 then gives the proper sight set- 
tings for this barrel for all ranges from 100 to 2,500 yards. 
For instance, at a range of 1,200 yards we would use the sight 
setting 1,300. 

It will be seen from the construction of this table that, know- 
ing the sight setting to be used to get the center of impact on 
the .500-yard trajectory of the short-range target and the cor- 
rect sight setting for hitting a target at any one range, we 
can get the correct sight settings for use with this barrel at all 
ranges from this table. We merely enter the table in the col- 
umn corresponding to the true range of the target and, in the 
five lines following the short-range elevation, find the nearest 
number to the sight setting found to be correct for the true 
range. The line in which the number is found is the line of 
proper sight setting for the barrel. Example: A gun required 
400 yards' sight elevation at the short range to get on the 500- 
yard trajectory. Ranging fire at a target 1,000 yards distant 
required a sight elevation of 1,150 to get in the target. The 
proper sight elevations to use with this gun are therefore found 
in the fourth line of the group having the number 400 to the 
left, because on this line is found the number 1,150 in the 
1,000-yard column. With this barrel a setting of 1,680 will be 
used for firing at 1,500 yards. 

It is best, however, to use a single range of from 400 to 600 
yards to determine the sight setting since the center of impact 
is more easily determined at the shorter ranges, and the firing 
can be done on ordinary rectangular targets. 



122 MACHINE-GUN FIRING MANUAL. 

This determination of the proper sight setting for each barrel 
should be made before commencing such field training as re- 
quires actual firing. After each 5,000 rounds, or oftener if 
the barrel is beginning to shoot low, a single carefully con- 
ducted ranging test at from 400 to 600 yards should again be 
fired and a new set of sight settings chosen if found necessary. 

The table of sight settings may be interpolated either for 
short-range sight values or for the full-range sight value, but 
this procedure will be unnecessary, as a rule, since an attempt 
to set a sight for a value such as 635 or 1,555 is a waste of 
time. 

The gunner should carry a card with the sight settings to be 
used for each barrel of his gun for each range. This is much 
preferable to an attempt to memorize these tabular values, par- 
ticularly as they will change from time to time as the gun wears. 



CHAPTER X. 
INSTRUCTION FIELD FIRING. 

GENEKAL. 

114. The organization having finished the record known dis- 
tance practice and determined the correct sight setting for its 
guns (par. Ill), practical instruction in the technical applica- 
tion of fire against field targets (Instruction Field firing) Is 
taken up. This includes: 

1. Indirect fire (Chap. XI), embracing adjustment by map 
from reports of observers, by compass and clinometer, by aim- 
ing point and clinometer ; adjustment without map, by compass 
and clinometer, by aiming stakes. 

2. Overhead fire. (Chap. XII.) 

3. Night firing. (Chap. XIII.) 

4. Adjustment of fire on visible target ( not masked ) . Choice 
of means — battle sight, single elevation, combined sights, search- 
ing. Ranging. Auxiliary aiming points or lines. 



MACHINE-GUN FIRING MANUAL. 123 

5. Fire for effect on straight and irregular lines both normal 
and oblique to the line of fire. Choice of aiming points. Meth- 
ods of distribution required in order to obtain various desired 
results. Designation, adjustment, wind corrections, rate, and 
volume to be incidental. 

6. Fire for effect on columns. Head on, flank oblique, on hill- 
side. Designation, adjustment, wind corrections, rate, and vol- 
ume to be incidental. 

7. Fire for effect on gun positions. Targets to represent 
machine guns or field pieces and to be concealed but not de- 
filaded. Adjustment from landscape sketch or range card. 
Designation, wind corrections, rate, and volume to be incidental. 

8. Fire for effect on moving targets — parallel, oblique, and 
perpendicular to the line of fire. Designation, adjustment, wind 
corrections, rate, and volume to be incidental. 

9. Fire for effect for the purpose of rendering a certain area, 
bridges, etc., untenable. When fire is opened, suitable targets 
will be used to represent an attempted crossing of this area by 
the enemy. 

115. The soldier, having made 65 per cent or over in the 
record known distance firing, will fire the record field-firing 
course (par. 136) over at least once before taking the qualifi- 
cation test. This firing will, if practicable, be fired over ground 
other than that to be used for the record problem. 

This practice immediately follows the instruction outlined in 
paragraph 114. 



CHAPTER XI. 
INDIRECT FIRE. 

116. Indirect fire is that class of fire in which the proper 
direction and elevation are given to the gun without the use of 
the tangent sight, or, when the tangent sight is used, by direct- 
ing the line of aim at some object other than the objective. 

No special instruments are provided for the machine gun for 
this purpose, and such angular measurements as are necessary 



124 MACHINE-GUN FIRING MANUAL. 

must be obtained with the compass, clinometer, and mil scale. 
The computation of the firing data from tnese measurements, 
taken in connection with the range, is greatly facilitated by the 
use of a slide rule. 

The tactical utility of indirect fire is not a subject for dis- 
cussion in this chapter which deals merely with certain impro- 
vised methods that have been found successful. 

117. Indirect fire may be divided into two general classes: 

(a) Indirect fire without a map. 
(&) Indirect fire with a map. 
In each of these two classes of fire, the problems to be solved 
are: 

(1) What direction in azimuth to give the gun. 

(2) What elevation to give the gun. 

There are several ways in which each of these problems may 
he solved. The particular combination of methods used in the 
solution of both problems will depend upon the terrain. In 
certain cases it may be possible to use any of the methods for 
determining either azimuth or elevation, while in other cases 
some of the methods may prove impracticable. 

INDIKECT FIEE WITHOUT A MAP. 

118. Indirect fire without a map demands that an observer 
must be able to see the target and that lie must be in com- 
munication with the crew at the gun. 

AZIMUTH. 

119. The proper direction in azimuth is given to the gun by 
so laying it that the axis of the bore forms the correct hori- 
zontal angle with a line whose direction is known to the fire 
controller at the guns. 

This line of known direction may be the magnetic meridian 
through the gun position, the line from the gun to an aiming 



MACHINE-GTJN FIRING MANUAL. 125 

point, or the line from the gun to a point, in the plane of site, 
that has been established on the near side of the mask. In this 
third case (drift and windage disregarded) the angle between 
the bore and the known line would be zero. 

One of the simplest methods of laying by magnetic meridian 
is by the ground map method. As an example, let the observer 
be at O (see PL 53), the target at T, the gun at G, and the mask 
at M. 




Plate 53. 

The observer at O finds the ranges OT and OG and then, to 
some convenient scale — say 1 foot =100 yards — he establishes 
the point T' on the ground' in the line OT and having the dis- 
tance OT' equivalent to OT on the reduced scale. In a similar 
manner the point G' is established. The observer now goes to 
the point G' and with a compass finds the bearing of the point 



126 MACHINE-GTTN FIRING MANUAL. 

T'. The lines G' T' and GT being parallel, this bearing is that 
of the target from the gun. 

The observer at O now communicates this bearing to the crew 
at the gun and they lay the gun for direction as follows : 

A compass is set up at the gun position, care being taken to 
remove the gun and all other iron equipment to a distance of at 
least 25 yards in order that there may be no abnormal deflection 
of the compass needle. The compass is now revolved until it 
registers the bearing sent by the observer. The sights of the 
compass are now used to line in an assistant who places a stake, 
stone, or other aiming target at some convenient point in front 
of the gun position as at A. Should it prove inexpedient to 
remove the gun and equipment from the position G, the compass 
may be set up at some convenient point in rear of the gun and 
then moved to the right or left until a point C is found at which 
the bearing of G is the same as that sent by the observer. The 
point A is then established as before. 

The point A having been established, the gun will be given 
its proper direction in azimuth when the sight is set at zero 
windage and the line of aim directed at A. 

This method may be varied to suit local conditions : 

For example, the ground map may be made at the gun posi- 
tion instead of at the observer's post, etc. 

When a natural aiming point is used, one must be selected 
whose deflection from the plane of fire is not greater than the 
arc of the windage scale. 

There are two general types of problems to be solved in deter- 
mining the amount of deflection to be used with a natural aim- 
ing point. These two types are : 

(a) When the observer is so close to the gun that there is no 
appreciable difference in this deflection as seen from his post 
and as seen from the gun position, and 

(&) When the observer is at such a distance from the gun 
that the angle subtended by target and aiming point at his post 



MACHINE-GUN FIRING MANUAL. 127 

differs materially from the angle subtended by these same two 
points at the gun position. 

In the first case the observer merely measures the horizontal 
angle between the target and the aiming point (a mil scale being 
the most convenient instrument for this purpose). Having ob- 
tained this angle, he converts it into points of windage and 
directs the gunner to set his sight accordingly. In converting 
mils to points, the following formula may be used : 

9 X mils 



Points =- 



10 



In the second case, the problem can be solved in a simple 
manner by the construction of a ground map. 




Plate 54. 

Referring to the figure, let G be the gun, T the target, A the 
aiming point, and O the observer. 



128 MACHINE-GUN FIRING MANUAL. 

The observer finds the ranges OA, OT, and OG. He then 
constructs his ground map to any convenient scale. This may 
be done without measuring any angles by placing the point 
A' in prolongation of AO, T' in prolongation of TO, and G' in 
prolongation of GO. The distance OA', OT', and OG' would 
be proportional to OA, OT, and OG. It will be seen that the 
angle T' G' A' is equal to the angle T G A, and hence the 
observer goes to G' and measures the angle subtended by T' 
and A'. Having measured this angle, he converts it into points 
of windage and directs his gunner to set his sight accordingly. 

The third method of giving the gun its proper direction in 
azimuth is by the establishment of an artificial aiming point 
on the near side of the mask. 

The establishment of this aiming point may be accomplished 
in three general ways: 

(a) By making a ground map. 

(&) By having two observers go to the mask and line each 
other in on the gun and target. 

(c) By having an observer line in the aiming point from high 
ground in rear of the gun from which he can see both the gun 
and the target. 

The ground map method is similar to that already discussed 
under the head of the compass. 

Referring to plate 55, let G be the gun, T the target, and O 
the observer. The observer measures the ranges OT and OG 
and the angle TOG. Then going to the gun position he 
establishes a point O' in the line OG, the distance O' G rep- 
resenting OG to the scale selected for the ground map. He 
then establishes the point T' in such manner that the angle 
T' O' G shall be equal to the angle TOG and the distance 
T' O' proportional to TO. The point T' then will be in the 
plane of fire and hence may be used as an aiming point with 
zero deflection. 

In the absence of an angle measuring instrument of greater 
accuracy than the mil scale, this method can not be depended 



MACHINE-GUN FIRING MANUAL. 



129 



upon for very precise results when the angle T O G is much 
greater than 200 to 300 mils. 

The method of alignment by two observers at the mask 
is as follows: 

The gun position having been selected, the two observers 
advance to the mask, establish themselves on the line joining 
the gun and target, and drive stakes to indicate these two 
points in the line. By means of these two points, this line 




Plate 55. 

is prolonged toward the gun and a third stake placed in the 
line and at some convenient distance (say, 25 yards) in front 
of the gun. A fourth stake is placed in the line about 50 
yards from the gun. 

To give the gun its proper direction in azimuth, it is placed 
in position in prolongation of the line established by the stakes 
and the line of aim directed at the nearest stake. 
106191°— 17 9 



130 MACHINE-GUN FIRING MANUAL. 

These aiming stakes also may be established by an observer 
in rear of the gun when high ground is available from which 
a view may be had of both gun and target. 

This method of determining the azimuth by the direct align- 
ment of aiming posts is quick and accurate and is the method 
to be preferred when local conditions will permit its use. 

, ... ELEVATION. 

120. To give the gun its proper elevation one must first deter- 
mine what that elevation is and then apply that elevation to 
the gun. 

Determining the elevation. — To determine the elevation re- 
quired it is necessary to know — 
The range, and 
The angle of sight. 

The range may be found by the ground-map method. For 
example (see figures in discussion of ground-map methods 
under "Azimuth" ante), the measurement of the distance 
GT' or G' T' to scale will give the range. 

When the observer is directly in front of the gun (for ex- 
ample, at the mask), he would find the distance to the target 
and to the gun. The sum of these distances would be the 
range. When the observer is directly in rear of the gun, he 
finds the range to be the difference between the distances to 
the gun and to the target. 

To find the angle of sight when the target is masked, it is 
necessary to know the range and also the difference in ele- 
vation, in feet or yards, between the gun and the target. 

These factors are determined from the post of the observer 
as follows : 

Referring to plate 56, let G be the gun, O the observer, T 
the target, and the line HH' the horizontal through the ob- 
server's post. 



MACHINE-GUN FIRING MANUAL. 131 

The observer measures the ranges OT and OG with a range 
finder and the angles T O H and G O H' with a clinometer. 
An example will best illustrate the further procedure. 




Plate 56. 



Let OG=500 yards, OT=1,200 yards, G O H'= 12 mils, 
and T O H=21 mils. Let it be assumed also that the range 
has been found (from a ground map or otherwise) to be 
1,500 yards. 

RM 

By the use of the mil formula W=jt™ it is found that H/ G= 

500X15 _ _ , , , „ _, 1200X21 ■ 
1000 = y aro ^ s ano - tnat -°- ™— — TOOO — — 2o.2 yards. 

The difference between these amounts is 25.2 — 6=19.2, i. e., 
the target is 19.2 yards below the gun, this amount being rep- 
resented in the figure by the distance L T. 

This difference in level between gun and target having been 
found, the angle of sight (L G T) is found by using the mil 
1000W 



formula M=- 



R 



1000X19.2 
Hence angle L G T= — 15QQ —12.8 mils. 

Having the range and the angle of site given, the elevation to 
be given the gun becomes the algebraic sum of the angle of de- 
parture and the angle of site, the angle of site being positive 
( + ) when the target is higher than. the gun and negative ( — ) 
when the target is lower than the gun. 



132 



MACHINE-GUN FIRING MANUAL. 



The angles of departure (in mils) for the various ranges (in 
yards) .are given in the following: 

Range table. 



Range. 


Angle of 
departure. 


•Range. 


Angle of 
departure. 


Range. 


Angle cf 
departure. 


100 


0.7 


1,100 


16.8 


2,100 


62.3 


200 


1.5 


1,200 


19.9 


2,200 


69.2 


300 


2.4 


1,300 


. 23.3 


2,300 


76.1 


400 


3.4 


1,400 


27.0 


2,400 


83.5 


500 


4.6 


1,500 


31.1 


2,500 


91.4 


600 


6.0 


1,600 


35.5 


2,600 


99.8 


700 


7.6 


1,700 


40.2 


2,700 


108.6 


800 


9.4 


1, 800 


45.3 


2,800 


118.1 


900 


11.6 


1,900 


50.7 ■ 


2,900 


128.2 


1,000 


14.0 


2,000 


56.5 


3,000 


138.9 



For example, assuming the range to be 1,000 yards and the 
angle of site to be +10 mils, then the required elevation would 
be 14 (from table) +10=24 mils. Had the angle of sight been 
— 10 mils, then the required elevation would be 14 — 10=4 mils. 

Applying the elevation to the gun. — Having determined the 
required elevation, the next problem is to apply this elevation 
to the gun. This may be done in any one of the following ways : 

(a) By the use of a quadrant; 

( b ) By the use of a level : or 

(c) By the use of an aiming point placed accurately in the 
line of site. 

In any case it is assumed that the gun has first been given 
its proper direction in azimuth before the elevation is applied. 

When a quadrant is used, the instrument is merely adjusted 
to the required elevation, placed on the gun, and the gun then 
elevated until the level bubble of the quadrant is centered. The 
gun then has the correct elevation. 



MACHINE-GUN FIRING MANUAL. 133 

To avoid the inconvenience and loss of time incident to veri- 
fying the elevation with the quadrant during the firing, it is 
usual, after the gun has thus been given its proper elevation, 
to clamp it fast, and then by manipulation of the rear sight and 
without changing the direction of the bore to direct the line of 
aim on some suitable aiming point. The correct elevation -is 
maintained thereafter by keeping the line of aim directed at 
this aiming point. If a suitable natural aiming point is not to 
be found, an artificial one, such as a stake or stone, may be 
placed at a convenient point in front of the gun. 

To use a level for the purpose of giving the gun its proper 
elevation, an aiming post is placed at some convenient distance 
(say, 25 yards) in front of the gun and in the plane of fire. 

The level is now placed on the gun and the gun elevated or 
depressed until it is level. 

The rear sight is set at zero and an aiming point is placed on 
the aiming post at the height at which it is cut by the line of 
aim. 

An example will best illustrate the further procedure. As- 
sume the range to be 1,000 yards and the angle of sight to be 
+13 mils. The required elevation is, therefore, +27 mils. Con- 
sulting the range table, it is seen that an elevation of 27 mils 
corresponds to a range of 1,400 yards. The rear sight, therefore, 
is set at 1,400 yards, the line of aim directed at the aiming point, 
and the gun will then have its proper elevation. 

To give the gun its proper elevation by the use of an aiming 
point placed accurately in the line of sight, it is assumed that 
an aiming post has been established in the plane of fire for the 
purpose of giving the gun its proper direction in azimuth. 

A clinometer is now set at the angle of sight and, from the gun 
position, its line of sight directed at the aiming post. Where 
this line of sight cuts the aiming post, an aiming point is estab- 
lished. The rear sight is now set at the true range, the line of 
aim directed at the aiming point, and the" gun will then be given 
its proper elevation. 



134 MACHINE-GUN FIRING MANUAL. 

There remains to be considered the methods used in giving 
the gun its proper elevation by the rise of a natural aiming point. 
There are, in general, two cases for consideration : 

(a) When the vertical angle between target and aiming point 
can be measured directly from a point approximately at the gun 
position ; and 

(b) When this vertical angle can not be so measured. 

In the first case the problem is easiest solved with a mil scale 
or with a sight scale. These methods are described in the 
Musketry Manual and in the pamphlets describing the mil scale 
and field glass. 

In the absence of any of these instruments, however, the 
problem may be solved with approximate accuracy by the use 
of the range table. For example, assume the range to be 1,000 
yards and the vertical angle between target and aiming point 
to be 13 mils — the target being above the aiming point. When 
aim is taken at the aiming point, the elevation to be used would 
be 13 mils more than 1,000 yards. As the elevation for 1,000 
yards is 14 mils (see range table), then the total elevation 
required would be 14+13=27 mils. From the range table it is 
seen that 27 mils corresponds to a range of 1,400 yards. Hence 
the gun is given its proper elevation when the sight is set at 
1,400 yards and aim taken at the aiming point. 

Had the target been below the aiming point instead of above 
it, then the elevation required would have been 14 — 13=1 mil, 
which would correspond to a sight setting of a little more than 
1,000 yards. 

When the vertical angle between target and aiming point can 
not be measured directly, it is found indirectly as follows : 

By the methods heretofore described, the observer finds the 
angle of sight from gun to target and the angle of sight from gun 
to aiming point. The difference between these two angles is 
the vertical angle required. This vertical angle having been 
found, the determination of the sight setting is the same as 
when the angle is measured directly. 



MACHINE-GUN FIRING MANUAL. 135 

INDIKECT FIRE WITH A MAP. 

121, Much of the indirect fire of trench warfare is done with 
a map, and hence proficiency in this class of fire is to be sought. 

The first thing to be done in map firing is to locate accurately 
one's own position on the map and also that of the target. 
As this is merely a matter of map reading, mention will be 
made only of the method of " squares " now largely in use. A 
discussion of this system will be found in the pamphlet of May, 
1917, on Maps and Artillery Boards, War Department Document 
No. 587. 

Having located the gun and target on the map, it is necessary 
to determine — 

( a ) The direction of the target ; 
(&) The range; and 
(c) The angle of sight. 

The direction is found by using a protractor to determine the 
compass bearing of the target, the protractor being oriented to 
the true north, magnetic north or grid north, according to cir- 
cumstances. The protractor also may be used to measure the 
angle to some suitable natural aiming point. 

The range is found by scaling it directly from the map. The 
angle of sight is found thus : 

First refer to the contours and determine the difference in 
level (in feet or yards) between the gun and the target. Then 
scale the range from the map. Now, having the range and this 
difference in level, the ansde of sight is found by using the mil 

1,000W 
formula M= — jt — ' care being taken to express the difference 

in level (W) and the range (R) in the same unit of measure 
as feet, yards, meters, etc. 

As an example, assume the range to be 1,500 yards and that 
the gun is on the 1,040 foot contour and that the target lies 
half way between the 1,050 and 1.060 foot contours. The level 
of the target, therefore, would be 1,055 feet and the difference 



136 MACHINE-GUN FIRING MANUAL. 

in level between gun and target would be 15 feet or 5 yards. 
Then applying the formula, 

1,000X5 
angle of sight — 1 50 q - =3J mils. 

Having the direction, the range and the angle of sight, the gun 
is laid by the most convenient of the methods already described 
lor firing without a map. 

After the technique of the solution of the single-map problem 
has been learned, leaders should be practiced in the registration 
of given map sectors and in opening fire quickly on any given 
point within that sector. 

THE CLEARANCE OF THE MASK. 

122. To determine whether or not the mask will be cleared 
by a given cone of fire, the following procedure is adopted : The 
gun is placed in position, given its proper direction and eleva- 
tion, and then clamped fast. Without moving the barrel, the 
tangent sight is now set at the range to the mask. If the line 
of aim is found to clear the top of the mask by not less than 
the amounts shown in the following table, then the 100 per cent 
cone will clear the mask. If the line of aim is found to be di- 
rected exactly at the top of the mask, then only the upper half 
of the cone will clear the mask. If the line of aim is found to 
be directed below the top of the mask by not less than the 
amounts shown in the table, then the mask will intercept the 
entire cone of fire. 



MACHINE-GUN FIRING MANUAL 
Table of mask clearances. 



137 



Range to 


Clearance, 


Range to 


Clearan:e, 


Range to 


Clearance, 


mask. 


in mils. 


mask. 


in mils. 


mask. 


in mils. 


100 


2 6 


1,100 


2.8 


2, 100 


5.6 


200 


2.6 


1,200 


2.9 


2,200 


6.3 


300 


2.6 


1,300 


3.0 


2,300 


7.0 


400 


2.6 


1,400 


3.2 


2,400 


7.9 


500 


2.6 


1,500 


3.4 


2,500 


9.1 


600 


2.6 


1,600 


3.7 


2,600 


10.5 


700 


2.6 


1,700 


4.0 


2,700 


12.2 


800 


2.6 


1,800 


4.3 


2,800 


14.2 


900 


2.6 


1,900 


4.7 


2, 900 


16.3 


1,000 


2.7 


2,000 


5.1 


3,000 


18.7 



123. Should it be desired to solve the problem of mask clear- 
ance without putting the gun in position, it may be done thus : 
Find the quadrant elevation required to hit the target and the 
quadrant elevation required to hit the top of the mask. If the 
target elevation exceeds the mask elevation by not less than the 
amounts shown in the table, then the mask will be cleared. If 
the two elevations are equal, then only the upper half of the 
cone will clear the mask. If the mask elevation exceeds the 
target elevation by not less than the amounts shown in the 
table, then the mask will intercept the entire cone of fire. 



CHAPTER XII. 
OVERHEAD FIRE. 

124. Overhead fire is fire delivered over the heads of one's 
own troops. It may be either direct or indirect. 

The tactical .application of overhead fire is not a subject for 
discussion in this chapter, which will deal only with its technical 
phases. 



138 



MACHINE-GUN FIRING MANUAL. 



The technical problem presented to" the machine gunner, when 
the tactical situation demands overhead fire, is whether or not 
one's own troops will be safe. 

125. Experience proves that, even with care, the errors in the 
determination of firing data combined with those of sight set- 
ting and aiming may amount in the .aggregate to what would be 
equivalent to a 15 per cent underestimate of the range. 

Assuming that this maximum error may be made, it is nec- 
essary to provide a further factor of safety, and this is done by 
demanding that, with this maximum error, the lowest shot in 
the sheaf shall clear the troops by not less than 10 feet and not 
less than 5 mils. 

Referring to plate 57, let G be the gun, T the target, UUU 
the upper limit of the sheaf, MMM the mean trajectory, LLL 




Plate 57. 



the lower limit of the sheaf, FL the feet of a man standing at 
the firing line, and H the head of the same man. 

Now, assuming the error in laying to have resulted in the 
center of impact falling short of the target by the distance MT, 
which is 15 per cent of the range, then overhead fire would be 
unsafe so long as the distance LH was less than 10 feet or 
the angle LGH less than 5 mils. 



MACHINE-GUN FIRING MANUAL. 



139 



126. To determine this in any concrete case, the range table 
given in Chapter XI is used in conjunction with the following: 

Table of safety angles. 



Distance 


Safety 


Distance 


Safety 


Distance 


Safety 


to troops. 


ang.e. 


to.troops. 


angle. 


to troops. 


angle. 


Yards. 


Mils. 


Yards. 


Mils. 


Yards. 


Mils. 


75 


102.4 


800 


27.7 


1,000 


65.5 


100 


77.3 


900 


30.5 


1,700 


73.0 


200 


41.6 


1,000 


33.7 


1,800 


80.8 


300 


30.8 


1,100 


37.6 


1,900 


89.6 


.400 


26.3 


1,200 


42.2 


2, COO 


98.9 


500 


24.3 


1,300 


47.2 


2,100 


109.2 


600 


23.9 


1, 400 


52.7 


2,200 


120.3 


700 


25.5 


1,500 


58.8 







The question of troop safety can be determined in the same 
manner as that of the clerance of masks. The gun being laid 
and clamped in position, the tangent sight is set at the range 
to the troops. If the line of aim is found to clear the highest 
point of defilade (the point FL in the above example) by not 
less than the amounts shown in the table of safety angles, then 
it is safe to fire. 

127. If the troops are hidden by a mask or if for any reason 
it is desired to solve the problem of troop safety without putting 
the gun in position, it can be done thus : Find the quadrant 
elevation required to hit the target and the quadrant elevation 
required to hit the troops. Then in order that the fire may be 
considered safe, the target elevation must exceed the troop 
elevation by not less than the amounts shown in the table. 

128. The following precautionary measures are taken when 
overhead fire is attempted : 

(1) A worn barrel is never used. 



140 MACHINE-GUN FIRING MANUAL. 

(2) It is necessary to find or make a solid foundation for the 
tripod or carriage. 

(3) All firing data must be carefully checked. 

(4) When clinometers are used, their accuracy must be veri- 
fied before firing. 

(5) A positive mechanical stop is used to prevent the depres- 
sion of the muzzle below the limits of safety. 

(6) Troops are notified before firing over them. 

(7) Corrections for atmospheric conditions, especially wind, 
are important. 

CHAPTER XIII. 
NIGHT FIRING. 

129. Occasions will frequently require that machine-gun fire 
at night be brought to bear on targets such as bridges, defiles, 
fords, rivers, or some obstacle in front of the position, wire en- 
tanglements, etc. This is accomplished by laying the gun in 
daylight and by the use of auxiliary aiming points. 

It is essential that all machine-gun men be thoroughly familiar 
with the methods involved ; therefore, all machine-gun organi- 
zations will have annually at least one night firing exercise 
using ball ammunition. 

The firing data and all necessary arrangements for firing may 
be made before dark, but the actual firing will not take place 
earlier than two hours after sunset nor later than two hours 
before sunrise. 

One of the following methods is suggested : 

(a) The illuminated face of a "night firing box." 

(fc) A stake silhouetted in front of a night firing box, or by 
means of a stake faced with luminous paint. 

Before nightfall the gun is placed in position. If a light 
gun, the muzzle rests in a notch cut in the top of a stake driven 
firmly into the ground, or with a heavy type of gun the position 



MACHINE-GUN FIRING MANUAL. 141 

of the tripod legs is marked by stakes. An auxiliary aiming 
point is provided by placing a night firing box or stake 12 § 
yards from the muzzle rest stake or muzzle of heavy gun at 
the night firing position and in line with the target. The gun 
is then accurately aligned on the target. By adjusting the rear 
sight slide and windage screw, the line of sight is brought to 
bear upon the aiming point without changing the direction of 
the bore. The reading of the rear sight in elevation and windage 
is recorded. 

When once located the position of the night firing box is 
marked by driving stakes at the back and sides ; this done the 
box may be removed and replaced when needed. 

For night firing the sight is set as recorded, the gun muzzle 
rested in the notch of the muzzle rest or legs of tripod put in 
marked positions, and the line of sight brought to bear upon 
the aiming point by means of the elevating and traversing gear. 
Fire for effect may then be opened at once. 

When circumstances place target and aiming point at approxi- 
mately the same elevation, the aiming point will be set a trifle 
to one side of the line of fire, and the necessary adjustment 
made in the line of sight by means of the windage screw. The 
night firing box is constructed so as to be invisible from the 
front and flanks. The auxiliary aiming point must never be 
placed so near the line of fire that a bullet may strike the box 
and expose the illumination to hostile view. 

130. Description of Night Firing Box. — This consists of 
a box one face of which is covered with transparent material 
marked as shown in plate 60. At 12^ yards from the eye, the 
interval betwen the horizontal lines subtends 2 . mils, and the 
intercept between the vertical lines 4 mils. 

Illumination is provided by an electric flash light, candle, 
lantern, etc., placed within the box. The illumined face is 
8 inches square. 



142 



MACHINE-GUN FIRING MANUAL. 




Plate 58. 



MACHINE-GUN FIRING MANUAL. 



143 



CHAPTER XIV. 

INDIVIDUAL QUALIFICATION TESTS FOR MEMBERS OF MACHINE- 
GUN ORGANIZATIONS. 

131. The examinations will be conducted by boards ap- 
pointed, in regiments, by the regimental commander. The 
boards for examination of special units will be appointed by 
the commanding officer of the unit to which the organization is 
attached. The board will --consist of three officers, one only of 
whom will be on duty with the organization undergoing ex- 
amination. The examination will take place as soon as prac- 
ticable after the completion of the instruction field firing 
(Chap. X). 

Only those officers and enlisted men whose names appear on 
the report of individual known distance practice (par. 291) 
as having made 65 per cent or over in the individual known 
distance practice (par. 110) will be examined by the board. 
Subjects : Value. 

A. Materiel 50, 

B. Determination of ranges 10 

C. Sight setting and recognition of targets 5 

D. Individual known distance practice 15 

E. Individual field firing 20 

Any candidate who falls below 65 per cent in any subject 

will not be permitted to proceed further with the test. 

Classification. 



Mini- 
mum gen- 
eral aver- 
age. 


Mini- 
mum in 
each sub- 
ject. 


Per cent. 

85 
80 
75 


Per cent. 
75- 
70 
65- 



Expert rifleman, machine gun 
Sharpshooter, machine gun... 
Marksman 



144 MACHINE-GUN FIRING MANUAL. 

132. A. Materiel — Value 50. — The examination will be com- 
prehensive and test the candidate's familiarity with the use 
and care of the materiel with which the machine-gun organi- 
zation is equipped : 

(A) THE MACHINE GUN. 

The candidate will be required : Value. 

1. To completely dismount the machine gun, including (1) 

barrel group; (2) receiver group; (3) working 
parts or firing mechanism, and (4) the mount 2 

2. To give name and explain the functions of all parts, 

their sequence of movement- in operation, and their 
adjustment, including the important parts of the 
rear and front sights 8 

3. To assemble gun and mount 2 

4. To completely dismount and assemble the machine 

gun, as enumerated under 1 above, blindfolded 8 

5. To give and explain points to be specially attended to 

in preparation for firing, during firing, and after 
firing, and to explain care, cleaning, and oiling of 
the gun . . 6 

6. To name and give use of contents of gunner's pouch, 

• tool or spare parts box, and accessories : 2 

7. To name parts, and give use and adjustment of load- 

ing tools 4 

(B) JAMS OE FAILURE TO FUNCTION. 

The examining board will state or give five conditions 
which prevent or impede functioning of the gun. 
The candidate will describe the cause of the con- 
dition and will demonstrate the means of remedy- 
ing the same _ : 18 



Total 50 

Note. — Machine guns will be considered completely dis- 
mounted when certain paragraphs of official pamphlets have 
been complied with. 



MACHINE-GUN FIRING MANUAL. 145 

Maxim : Paragraphs 1 to 10, inclusive, pages 26, 27, and 28, 
with the exception that paragraph 3, page 27, should be changed 
to require the disassembling of the lock. Page 33, packing, 
"For the rear bearing." " For the front end." (Ordnanc* 
Department Handbook of the Maxim Automatic Machine Gun, 
cal. .30, Model 1904, revised to July 5, 1916.) 

Tickers : Paragraphs 1 to 10, inclusive, pages 28, 29, and 30. 
Page 30, packing, " For the rear bearing " and " For the front 
end." (Ordnance Department Handbook of the Vickers Ma- 
chine Gun, Model 1915, dated Mar. 19, 1917.) 

Benet-Mercie : Paragraphs 1 to 17, inclusive, pages 30, 31, 
and 32, second paragraph, page 38. (Ordnance Department 
Handbook of Automatic Machine Rifle, cal. .30, Model 1909, 
revised to July 31, 1916.) 

Lewis : Dismounting, general, page 27, as given. Buttstock 
group, page 28, not dismounted. Receiver group, page 29 ; 
rear sight will not be removed from feed cover. Mainspring 
group, page 30, as given. Guard group, pages 30-31, not dis- 
mounted. Bolt complete, page 31, as given. Operating rod, 
page 32, not dismounted. Barrel group, pages 32-33, the barrel 
and gas chamber band will not be dismounted from the radiator. 
(Handbook Savage Arms Co., Lewis Automatic Machine Rifle, 
Model 1916.) 

Note. — The following table is given only as a guide for ex- 
amining boards in the tests for knowledge of the materiel un- 
der "A." This table gives a fair average time in which re- 
placements should be made by well-instructed men and must 
not be construed under any circumstance as having any value 
in the test or increasing the mark attained by any man for 
performing any given operation in less time than that given 
in the table. 

The weight to be given any candidate should be based on — 

1. An apparent knowledge of the sequence of movements 
necessary to remove or replace any given part ; or 
106191°— 17 10 



146 



MACHINE-GUN FIRING MANUAL. 



2. The avoidance of unnecessary movements in removing or 
replacing any part ; or 

3. The dexterity with which he performs any operation ; or 

4. The use of proper tools for making replacements ; or 

5. The accuracy and time in which he determines the cause 
of a stoppage. 

These tests will commence with the gun completely assem- 
bled and properly adjusted ready to fire. 

In dismounting the proper group must first be removed and 
then the designated parts dismounted. 

In assembling the test is completed when the gun is adjusted 
and ready to fire. 

Maxim or Vickers Guns, 





Dismount. 


Assemble. 


Parts, given in detail. 


Min- Sec- 
utes. ends. 


Min- 
utes. 


Sec- 
onds. 


1. Barrel group 


2 




30 
30 

5 
10 


4 





(a) Recoil plates r and 1. 

(b) Crank. 

(c) Barrel. 

Firing mechanism 




(a) Lock. 
(6) Trigger bar. 
2. Working parts 




1 

15 
5 
10 




(a) Spring box. 
(6) Recoil spring, 
(c) Fuse and links. 
3 . Feed box 




5 


4. Nozzle and barrel disk 




10 


5. Handle block. 

(a) Trigger, 
fi. To replace asbestos packing 






(a) Front ! " ' ! 




(6) Rear ' ' 




1 ! 





MACHINE-GUN FIRING MANUAL. 



14T 



LEWIS MACHINE GUN. 

Note. — The barrel group will not be dismounted in any man- 
ner involving a time element. There is great danger of cross- 
threading the delicate union between the gas cylinder and gas 
chamber, the chamber and gas band. The rear end of the gas 
cylinder is easily injured where it fits into the rear locking piece. 
An attempt to force the barrel into a reversed gas band might 
cause irreparable damage to the gas band, barrel, and radiator. 



Table showing in detail groups and parts to be dismounted and 
assembled. 





rismount. 


Assemble. 


Parts, given in detail. 


Min- 
utes. 


Sec- 
onds. 


Min- 
utes. 


Sec- 
onds. 


1. Constituent groups 


1 

2 






2 
3 





(a) Buttstock group. 
(6) Receiver group. 

(c) Mainspring group. 

(d) Guard group. 

(e) Bolt and rod group. 
(/) Barrel group. 

2. The receiver group 





I. Feed cover. 

(a) Magazine pawls spring. 
(6) Stop pawl. 

(c) Rebound pawl. 

(d) Cartridge guide pin. 
(ej Cartridge guide. 

(/) Cartridge guide spring. 

II. Feed operating arm. 
(a) Feed pawl. 

(6) Feed pawl spring. 

III. Ejector cover. 

IV. Ejector. 





14S 



MACHINE-GUN FIRING MANUAL. 



> 



Table snoiving in detail groups and parts, etc. — Continued. 





Dismount. 


Assemble. 


Parts, given in detail. 


Min- 
utes. 


Sec- 
onds. 


Min- 
utes. 


Sec- 
onds. 


3. Working parts groups 

I. Operating rod. 

II. Bolt. ' 

, (a) Feed operating stud. 

(b) Both extractors. 
: III. Gear casing. 

(a) Collet pin. 
(&) Gear. 

(c) Mainspring in casing. 

(d) Collet. 


2 


30 


2 


30 



AUTOMATIC MACHINE RIFLE, MODEL 1909 (BENET MERCIE). 


Barrel group 


1 


38 


2 





(a) Regulator. 










Receiver group 


4 


40 


8 


56 


(a) Ejector. 










(&) Ejector spring. 










(c) Ejector cap. 










(d) Cartridge stop. 










(e) Cartridge stop spring. 










(/) Cartridge stop holder. 










(g) Cover plate. 










(h) Cover plate washer. 










(i) Cover plate screw. 










(j) Feed piece. 










(k) Feed piece spring. 










(1) Fermature nut. 










(m) Locking nut. 










Firing mechanism group 





58 


1 


44 


(a) Actuator. 










(&) Actuator spring. 










(c) Breech block. 










(d) Firing pin. 










(e) Extractor. 










(/) Extractor spring. 











MACHINE-GUN FIRING MANUAL. 149 

133. B. Determination of Range — Value 10. 

Credits. 

(a) Range-finder adjustment 0.5 

(&) Range finding ; 3 

(c) Mil scale : 4 

(d) Estimation of distance 2.5 

Total _" 10. 

The candidate will be tested on terrain away from class A 
range. The self-contained base-range finder and musketry rule, 
model 1916, will be used. 

(a) Adjustment of Range Finder. — Halving and distance. 
(As prescribed in handbook for the particular instrument with 
which organization is equipped.) For which a value of 0.25 
will be given for each of the halving and distance adjustments, 
a total value of 0.5. 

(&) Range Finding. — Three trials with self-contained base 
range finder at ranges from 600 to 1,800 yards, using well-defined 
objects as targets, aiming points, or registration marks. 

The range finder will be in adjustment, set up, put in gear, 
and focussed, but will be out of direction at the beginning of 
each trial. 

The object to which the range is to be found having been 
identified by the candidate, the examiner commands, for ex- 
ample : 

1. Object, that (name of object, as tree, house, target, etc.): 

2. Measure the range. 

At the last word of the last command the candidate measures 
the range, and announces, for example, 950. He then steps clear 
of the instrument. 

No credits are given if the range announced is not within 5 
per cent of the correct range as determined by the board with 
the instrument used. 



150 



MACHINE-GUN FIRING MANUAL. 



If the range has been correctly measured and announced 
with the limits prescribed, credits are given for each as follows : 





Within 3 per 
cent of range. 


Within 5 per cent 
of range. 


Time in seconds, exactly or less than 


15 


25 


30 


15 


25 


30 


Credits 


1 


.9 


.8 


.75 


.7 


.65 







(c) Mil Scale. — The candidate will be provided by the board 
with a suitable mil scale, or may use his own instrument if he 
prefers. 

Four tests will be given : 

1. The determination of the deflection between a reference 
point and an announced target. 



Error in 





1 


2 


3 


4 


5 


6 


7 


8 


9 


10 o r 


mils. 






















more. 


Credits. . . . 


1 


0.9 


0.8 


0.7 


0.6 


0.5 


0.4 


0.3 


0.2 


0.1 






2. The determination of a prescribed front expressed to the 
candidate in mils. 

3. The determination of the range to an objective from 800 
to 1,500 yards distant. This objective to be established by the 
board and to subtend a front of between 150 and 250 mils. 



Error in range. 



Credits . 



5 per cent 
or less. 



6per cent 



7 per cent 



8 per cent 



0.4 



9 per cent 



0.2 



10 per 

cent or 

greater. 





4. The determination of a sight setting appropriate for use 
with a given target and auxiliary aiming point. 



MACHINE-GUN FIRING MANUAL. 



151 



(d) Estimate of Range. — The candidate will be taken to 
ground away from the class A range and be given five trials, 
three from a standing position and two from a prone position. 
The objectives will be arranged at distances varying from 200 
to 1,200 yards and will be physical objects, standing or prone 
men, grouped or single, appropriate to the distance. 

No credits will be given in the following cases : 

1. If the error in the estimated distance is greater than 15 
per cent. 

2. If the time taken in announcing the estimate is more than 
25 seconds. 

Credits for each trial will be given as follows : 



Within 10 per 
cent of range. 



Within 15 per 
cent of range. 



Time in seconds , exactly or less than . 
Credits 



15 

0.5 



20 
0.3 



25 
0.2 



15 
0.2 



20 
0.15 



25 

0.1 



134. C. Sight Setting and Recognition of Targets — Value 
5. — The candidate will be so posted behind cover that the 
target figures' are invisible. The location of the target will 
then be described to him by the board — using the clockface 
and mil system — announcing the true range and an arbitrary 
windage. If the terrain does not include reference points suffi- 
ciently distinct, the board will cause the same to be established. 

At the command "ready" the candidate will step to a posi- 
tion from which the target may be seen ; " find " the target ; 
set his sights as ordered and adjust his machine gun on the 
designated target. 

No credits will be given in the following cases : 

1. When the gun is not pointed at the correct target. 

2. When the sight is not set at the announced elevation and 
with the windage ordered. 



152 MACHINE-GUN FIRING MANUAL. 

185. D. Individual Known Distance Practice. — The per- 
centage adopted by the board is that entered on the record of 
individual known distance record firing and qualification test 
by the company commander under paragraph 289A. 

136. E. Individual Field-Firing Test. — To be so arranged 
that it may be fired on a class A range at stations where a 
class B range is not available. 

At least five groups of targets will be used. (These may 
radiate from a common firing point.) The targets will be on a 
beam, and only the group to be fired at will be visible. 

Men awaiting test will remain in a position from which the 
targets can not be observed. 

1. Range. — Between 500 and 1.200 yards. 

2. Targets — A group of eight prone figures so spaced as to 
cover a front of 10 yards (or 48? inches between centers). 

3. Firing. — At discretion of candidate. 

4. Ammunition. — 60 cartridges per man. This to be loaded 
by the individual who is to fire it in two clips, belts, or maga- 
zines containing 30 rounds each. 

5. Mount. — As issued. 

6. Equipment. — The firer will be equipped with a gunner's 
pouch, tool box, or other accessories necessary to operation of 
the gun. 

7. Sight. — Leaf or battle, as determined by firer. 

8. All firing will be " automatic." 

9. Time. — Time, two minutes, taken from the arrival at the 
firing point with the gun. The signal for ceasing fire will be 
communicated by whistle. 

10. Loading. — By an assistant. 

11. Jams. — When jams occur time is taken out until the gun 
has been made to function. The candidate is then allowed to 
continue the firing in the time remaining to his credit. 

12. Score for fire effect. — Each figure hit will count as 
follows : » 



MACHINE-GUN FIRING MANUAL. 153 



500 yards__ 2. 14 

600 yards 2.19 

700 vards 2. 23 

800 yards 2. 28 



900 yards 2. 33 

1,000 yards 2.41 

1100 yards 2. 5 

1,200 yards 2.62 



13. Coaching. — None allowed after the candidate has identi- 
fied his target. 

14. Cover. — A sandbag revetment not less than 8 feet in length 
and 3 feet in height, with loopholes not to exceed 100 square 
inches in area. 

15. Assistant. — The candidate will be furnished an assistant 
who may assist in, advancing the gun, ammunition, and acces- 
sories to the firing position and setting up the gun. He will 
further assist in loading, regulating gas pressure, and reduction 
of jams. 

His duties will be limited strictly to those described above. 

16. Procedure. — When directed by the board the candidate, 
leaving his assistant at least 30 yards to the rear, will advance 
to the artificial cover provided and be shown his targets for 
identification. No determination of ranges will be permitted 
at this time. 

He will then advance the gun by hand to the firing position, 
go into action, determine the range by any means he may desire, 
and open fire for eifect. 

At the whistle signal for ceasing fire, or on firing the 60 car- 
tridges allowed, he will retire 20 yards. 

17. Credits. — The board will determine credits for the test 
on the following basis : 

Value. 

1. Advancing under cover and going into action (celerity 

and use of cover considered) 1 

2. Use of cover while firing ; ^_ 1 

3. Retiring under cover from action (celerity and use of 

cover considered) 1 

4. Effect of fire (figures hit) 17 

Total 20 



PART III. 



COMBAT FIRING. 



CHAPTER I. 
FIRE PROBLEMS. 

137. The solution of a tactical problem may involve a con- 
sideration of many incidental problems, including questions of 
supply, maneuver, transportation, policy, psychology, infantry 
fire, machine-gun fire, artillery fire, etc. 

The subject of fire action (infantry, machine guns, or artil- 
lery), is taught by means of fire problems. 

A tactical problem may or may not include a fire problem as 
an incident to its solution. A fire problem, however, is always 
a part of a tactical problem, fire power being a physical means 
to a tactical end. 

Therefore the tactical methods adopted in the solution of a 
fire problem should receive full consideration in judging the 
problem as a whole. 

138. Fire problems are of two general types : First, those 
designed to give commanding officers (battalion, regimental, 
brigade, and division) a knowledge of and practice in the utiliza- 
tion of the fire power at their command for the accomplish- 
ment of given tactical missions ; second, those designed to give 
practice to subordinate commanders and their organizations in 
applying their technical skill in the use of their fire power in the 
accomplishment of their missions. 

154 



MACHINE-GUN FIRING MANUAL. 155 

139. These two types of problems are quite different in their 
subject matter. The commanding officer considers the firearms 
in the hands of his troops merely as so many tools with which 
to do a certain piece of work. His problem concerns the plac- 
ing of his troops in such position that they may develop fire 
power commensurate with the assigned task. Th,e question is 
therefore a tactical one, the solution of which requires, not only 
tactical ability but a technical knowledge of the limitations and 
capabilities of the material in the hands of his troops. 

140. At the outset of a campaign, the machine-gun com- 
mander might be depended upon for advice as to these technical 
details, but the casualties occurring in field operations of any 
magnitude are more than apt to result in the command of ma- 
chine-gun organizations pertaining to regimental and smaller 
units falling to men of immature judgment. Disaster might 
well result at such a time, if the commanding officer's judgment 
was based upon his unguided opinion rather than upon sound 
knowledge of the facts of applied technique. 

141. Tactical ability and facility in command is developed 
by means of tactical walks and rides, terrain exercises, war 
games, and maneuvers. With a view to training of officers for 
command, commanding officers of posts and regiments are 
responsible that all officers acquire not only a thorough famili- 
arity with the tactical limitations and capabilities and uses of 
the machine gun but a thorough knowledge of machine-gun 
materiel, technical methods of fire, etc. To this end the avail- 
able machine-gun organizations should serve as a school for 
instructing other officers of the command. 

142. The training of machine-gun commanders involves both 
technique and tactics. 

In a tactical way he must be able, when called upon to do 
so, to offer sound advice to his commanding officer as to the 
employment of his machine-gun organization in the prospective 
combat. Also there will be times when failure of communica- 
tion will place the machine-gun commander out of touch with 



156 MACHINE-GUN FIRING MANUAL. 

his commanding officer. In such a case the responsibility for 
correct tactical decisions rests upon the machine-gun com- 
mander. 

143. In a technical way, the machine-gun commander's 
problem is somewhat as follows : 

Based entirely upon the directions received from his com- 
manding officer, or upon these directions supplemented by 
such tactical discretion as is allowed him, he arrives at the 
conclusion that the tactical requirements of the situation de- 
mand that he — 

1. Occupy a given position, 

2. With a given number of guns, and 

3. Fire upon a given target 

4. For a definite purpose 

5. At a given time, and 

6. For a given length of time. 
His technical problem then becomes — 

1. How to reach the position ; 

2. How to occupy the position ; 

3. How to secure the safety of his transport ; 

4. How to keep his guns supplied with ammunition for 

the task before them ; 

5. How to replace casualties ; 

6. How to keep in communication with his commanding 

officer, with the subdivisions of his unit, and with 
neighboring troops; and 

7. How to make his fire effective. 

The development of a tactical situation may require the 
solution of a series of such technical problems. 

144. Whether designed for the training of officers or of 
-machine-gun units, a course of fire problems should include as 
many of the probable phases of combat as possible. 

Thus, such a course would include the use of machine 
guns in — 

The service of security. 
Attack. 



MACHINE-GUN FIRING MANUAL. 157 

Defense. 

Withdrawal. 

Delaying actions. 

Attack and defense of convoys. 

Siege operations. 

Trench warfare, etc. 
A course in fire problems should also be made progressive. 
At first such problems would involve a single tactical principle 
and simple technique, while toward the end of the course the 
problems are so framed as to be a severe tax upon the tactical 
skill and technical ingenuity of the participants. 

In addition to the methods employed in the training of 
officers ( map problems, tactical walks, etc. ) , field firing exercises 
are used in the training of machine-gun units. 

145. The Construction of Fiee Problems. — Depending upon 
their purpose, fire problems may be divided into two general 
classes as stated above : 

(a) Those designed for the training of officers in general. 
(&) Those designed for the training of machine-gun com- 
manders. 

146. Problems designed for training of officers in general 
are usually without troops, or. if troops are used, then the use 
of ball cartridges is exceptional. 

The usual problem of the commanding officer is to express 
the accomplishment of his mission in terms of fire effect, to 
determine what troops are required to produce that fire effect, 
and then to issue an order that will carry his decision into 
effect. In a word, his problem is to translate tactics into 
technique. 

The statements of such problems should be as simple and con- 
cise as consistent with clearness. The solution of the problem 
may require any one or more of the following : The estimate of 
the situation, the decision, the orders. 

It is seen that the commanding officer's problem (assuming a 
decision to fight) as well as that of the commander of a sub- 



158 MACHINE-GUN FIRING MANUAL. 

ordinate unit higher than the company is one largely of deploy- 
ment and the assignment of objectives or sectors. 

147. Machine-Gttn Commander's Problems. — The individual 
training of the machine-gun commander in the application of 
fire is by means of fire problems similar to those employed in 
the training of other officers — i. e., map problems, terrain exer- 
cises, tactical rides and walks, etc. 

In the training of the machine-gun commander in the actual 
handling of his unit under simulated combat conditions the fire 
problem takes the form of a field firing exercise. 

A field firing exercise is a fire problem solved by troops on 
the ground, the enemy (or such portion as concerns the troops 
participating) being represented by targets, and the troops 
being supplied with ball ammunition to be used (or not) under 
the direction of their leader. 

148. Tactical problems which do not include fire problems 
may be presented in the guise of field firing exercises — i. e., the 
enemy being represented by field targets and the troops being 
supplied with ball cartridges. Such problems are for the pur- 
pose not only of testing the leader's judgment in the application 
of fire, but also of impressing upon the participants that a 
problem combining a belt full of ammunition and a visible 
enemy does not always require fire action for its correct solu- 
tion. 

149. The field-firing exercise limits the action of the leader 
to a much greater extent than do other forms of fire problems. 
These limitations are necessary, first, because it usually will 
prove impossible to manipulate the targets in such a manner 
as to present a logical situation to meet all of the many possible 
solutions of the problem, and, second, because precautions for 
safety usually demand that the direction of the fire be confined 
within the limits of a certain definite arc. 

As a consequence of these limitations the field firing exercise 
usually is confined to the representation of a single phase or 
episode of an engagement. Such episode might be covering an 



MACHINE-GUN FIRING MANUAL. 159 

assault, resisting an assault, resisting a counterattack, cover- 
ing a withdrawal, covering an outpost position at night, etc. 

Like other tactical problems, the field firing exercise is con- 
structed with a view to imparting a. lesson in tactics. An ex- 
tended series of these exercises would be so framed as to in- 
clude the application of all possible phases of technique to the 
accomplishment of tactical missions. 

In order to preserve the realities of war, the problem, when 
practicable, should be laid on ground that is unfamiliar to the 
participants. 

150. The targets representing the enemy must present a 
logical appearance. Their position, arrangement, and move- 
ment should be such as might be expected from well-trained 
troops under the conditions of the exercise. 

As far as the mechanism of the target range will permit, 
there should not be left to the imagination any visible action 
of the enemy that can actually be represented by manipulation 
of targets. 

Representing, by targets, the troops with which it is assumed 
the organization is acting adds interest and reality to the 
exercise. 

151. In presenting all possible phases of combat, there will 
be problems that must be solved with a limited ammunition 
supply. In such cases the actual amount of ammunition sup- 
posed to be available is given in the statement of the exercise. 
As a rule, it is better to have the troops take the field with the 
ammunition they would naturally carry. The expenditure of 
this ammunition is regulated by the umpire, who causes the 
firing to cease when he considers that the volume of fire has 
been sufficient for the purposes of the exercises. 

There are practical difficulties, however, that prevent a strict 
adherence to this principle. The majority of machine-gun prob- 
lems will require for their solution only a small part of all the 
ammunition that is carried in the field equipment. Ammunition 
deteriorates more rapidly after it has been removed from the 



160 MACHINE-GUN FIRING MANUAL. 

original cases. Thus, to avoid having large quantities of loose 
ammunition on hand after the completion of any firing, the 
amount of ammunition actually carried in any exercise usually 
would not be more than about 30 per cent in excess of the amount 
which the umpire decides should be expended. 

In informing the organization commander of the amount of 
ammunition to bring to the range, the umpire would state, in 
effect, " For this exercise it is assumed that your ammunition 
chests are full (or that the supply has been reduced to 2,500 
rounds per gun). Of this assumed supply you will carry only 
900 rounds per gun loaded in belts (strips or magazines)." 

152. The umpire should estimate the amount of time re- 
quired for an organization to complete an exercise. Organiza- 
tions that follow should be ordered to report on the range at 
such an hour as to require the minimum loss of time in waiting 
their turn. 

An exercise loses much of its instructional value if the par- 
ticipants have any advance information as to number, location, 
arrangement, or movement of targets, or, in fact, if they have 
any knowledge of the exercise conveyed to them in any manner 
prior to their taking part in it. Particular care is necessary 
in order to prevent this advance information reaching troops 
that are waiting their turn to fire. 

153. The form of the written statement of a field-firing 
exercise differs in some particulars from that of other tactical 
problems. 

In the ordinary tactical problem the leader is presented with 
a statement of the situation and, based upon that situation, 
there is required, perhaps, his estimate of the situation, his de- 
cision, his orders, the execution of those orders by his subordi- 
nates, etc. This is the complete statement of the problem. 

154. In the field-firing exercise, the leader is confronted with 
similar situations and requirements, but there is a second part 
to this statement which the leader does not see before his solu- 
tion of the problem is complete. 



MACHINE-GUN FIRING MANUAL. 161 

This second part of the statement is for the information of the 
umpire and the range officer. 

In it are included statements covering as many of the follow- 
ing points as are essential : 

1. The object of the exercise. The tactical and technical les- 
sons it should impart. Stress is laid upon the mission and what 
must or may be done to accomplish it. 

2. The procedure is given in considerable detail. This would 
include such further information as is given the troops and also 
a description of the manner in which the targets are to be ma- 
nipulated in order to represent the action of the enemy. 

3. A statement as to the number, kind, location, and arrange- 
ment of targets is given. This would include also a statement 
of what shelter is required for markers and the number of men 
required as a pit detail to manipulate the targets. 

4. A complete statement as to the system of communication 
required between pits and firing points and elsewhere about the 
range. The number of agents of communication (signalists, 
buzzer or telephone operators, messengers, etc.). 

5. A statement as to the necessary precautions for safety, 
roads and routes on which traffic must be stopped, number of 
range guards required to perform this duty, as well as their 
posts or beats. 

6. A sketch showing location and arrangement of targets, 
position of firing points, dangerous area, posts of range guards, 
etc. 

155. In writing problems that are to be carried out on a 
range where a permanent range officer is in charge, the details 
as to agents of communication, range guards, pit details, etc., 
may be omitted, the attention to these details being part of the 
range officer's duty. 

156. In the solution of problems pertaining to brigades and 
divisions it usually is assumed that the student is the brigade 
or division machine-gun officer. 

106191°— 17— — 11 



162 MACHINE-GUN FIRING MANUAL. 

The requirements might be as follows : 

1. The commanding officer asks your advice as to the use of 
the machine guns in this case. How would you advise him? 

2. State briefly your reasons for this advise or make a de- 
tailed estimate of the situation. 

3. What orders are necessary to carry this decision into 
effect? 

4. Your commander has outlined his plan of action to you 
and directs that you write the portion of the order pertaining 
to the machine guns. 

5. What action will you take in order to carry out the order 
issued under 4? 

6. In a case requiring verbal orders, give them orally and 
then prepare a brief written statement embodying your esti- 
mate of the situation and your decision. 

Similar problems may be used involving the employment of 
machine-gun units by regimental, battalion, and company com- 
manders of infantry and cavalry. 

157. In field-firing exercises, it is usual to have only the 
machine-gun units participate. 

The necessity for arranging the targets to meet certain pre- 
conceived conditions usually demand that the machine-gun unit 
be acting under certain definite orders that are embodied in the 
statement of the problem. It will sometimes be possible, how- 
ever, to call on the machine-gun commander to issue tlie order 
to his unit in the name of his commander and then to require 
him to carry out that order. 

158. A complete set of combat problems for machine guns 
should include the following: 

1. Rencontre problems. — A machine-gun organization is pre- 
sumed to be part of an advance guard on the move and with 
guns packed. A meeting with the enemy is presumed to occur 
and the advance guard commander gives the machine-gun com- 
mander a mission to hold a certain point or to support the ad- 
vance guard in its attack on the enemy or to assist in some other 



MACHINE-GUN FIRING MANUAL. 163 

way in the action. The ranges are usually under 500 yards and 
rarely over 800 yards. Time is a most important element in 
the correct solution of this class of problems. 

2. Problems in supporting an attack. — The machine-gun com- 
mander is given a mission to support an attack from a point on 
the flank or to guard a flank during an attack or to assist by 
firing over the advancing line from a height. The ranges may 
be between 600 and 1,200 yards, with an advance of the machine- 
gun organization in some cases to 500 yards or less. Time is 
usually ample for the preliminary preparation, but prompt 
opening of fire at the proper time is important. 

3. Problems in defense. — The machine guns may have a posi- 
tion at a supporting point and open fire at the time and at the 
objective named by the commander of the supporting point. In 
another case, the machine-gun organization may be in reserve, 
under cover, and be rushed up to a position to fire on some 
target at an opportune time. The ranges are usually under 600 
yards, since the fire of machine guns in this case is properly 
withheld until the enemy begins his charge. Fire on targets 
representing cavalry charging from the front or flank comes 
under this head. Time is usually sufficient for preliminary 
preparation, but prompt opening of fire is necessary. 

4. Problems in trench warfare. — Single guns are covered by 
intrenchments against fire from the front and have, for a mis- 
sion, the stopping of the enemy's charge by flank fire over the 
area immediately in front of the wire entanglements. The 
ranges are from 150 to 50 yards against rapidly moving targets. 
Quick action is required. 

5. Rear-guard and delaying -action problems. — The idea in 
these cases being to force the enemy to deploy as soon as he 
comes in sight, the firing will be at targets representing large 
formed bodies of the enemy at long ranges, say 1,200 to 1,800 
yards or more. Time is often a consideration but is, in general, 
a relatively unimportant factor unless there are unnecessary .de- 
lays in opening fire. 



164 MACHINE-GUN FIRING MANUAL. 

6. Problems in firing on masked targets. — In this case the 
target is not visible from the guns but is masked by some natural 
features. If, however, the target can be seen by observers at 
one or more positions on the flank or flanks or from higher 
ground to the rear of the guns, then the fire of machine guns 
can be made effective. Firing of this character may be held at 
ranges of from 800 to 1,800 yards or more. A reasonable time 
for the more complicated preparation for fire must be allowed. 

7. Problems where the gum are masked. — In this case the 
organization must use a method of indirect fire modeled after 
that of the field artillery. The tactical situation might require 
this type of fire when the machine guns are within effective range 
of hostile artillery. The range to the targets may be anywhere 
from 400 to 1,800 yards or more. As in problems under case 6 
a reasonable time foi preparation must be allowed. 

8. Problems in night firing. — These may be of two kinds. In 
the first the target is illuminated by searchlight or other means. 
In the second case the guns are set up by daylight covering a 
bridge or road, the mission being to stop the advance by night of 
an enemj^ over the road or bridge. The ranges in either case 
will rarely exceed 600 yards and prompt opening of fire is de- 
manded. 

9. Problems in firing at aeroplanes. — Kites of special forms, 
towed by automobiles, will serve as targets. The results of 
such firing should be very carefully analyzed, and it should be 
made perfectly clear to all that the greater speed and flying 
height of real aeroplanes will require altogether different and 
much greater corrections in sight elevations and point of aim 
in front of the machine. Ranges of the kites will usually be 
from 300 to 800 yards, the kites actually flying at heights of 300 
to 400 yards. All time elements are vital. 

159. Problems under 1, 2, 3, 7, and 8 can be handled on "A" 
ranges as actual combat problems with ball cartridges. It will 
often be possible on the larger "A" ranges to handle firing prob- 
lems under 4, 5, and 6, but problems under 9 can not be fired 



MACHINE-GUN FIRING MANUAL. 165 

on "A" ranges on account of the elevation which must be given 
to the guns and the resulting distribution of the bullets over a 
wide area. 

It is, of course, desirable to use " B " ranges for all combat 
firing on account of the increase in interest inspired by new 
terrain and the nearer approach to service conditions possible 
on such ranges, but combat firing can always be held and held 
with much value to all concerned, even if an "A" range has to be 
utilized for the firing. 



CHAPTER II. 
DRILL EXERCISES. 

160. It is essential that the mechanism of combat problems 
be thoroughly understood before any are attempted with ball 
ammunition, and this can always be done by adequate prelimi- 
nary combat-drill exercises on any available terrain. 

In this preliminary work especial attention should be paid to 
target designation, fire orders, taking up positions, questions 
of cover for guns, men, and transportation, and details of the 
technique of preparation for and adjustment of fire. It is 
presumed that the members of the organization have been 
trained in their individual duties before combat firing is 
attempted. 

161. The target for these exercises may be either repre- 
sented, outlined, or assumed. When represented or outlined, 
either men or silhouettes may be used for the purpose. The 
limits of the objectives are indicated by flags and may include 
the entire line or only a portion of it. 

162. The unit (company, platoon, or squad) is halted at 
some point from which it is not possible to obtain a view of 
the target. The instructor calls the leader forward to a point 
from which the target is visible and at the same time causes the 



166 MACHINE-GUN FIRING MANUAL. 

flags to be displayed at the target. He points out the target 
to the leader and informs him that the flags mark the flanks 
of his objective. The instructor further informs the leader that 
these flags will be removed before his unit is permitted to come 
within view of the target and that therefore the flanks of the 
objective must be fixed in the mind by reference to natural land- 
marks. When the leader informs the instructor that he has 
the target definitely located with reference to natural land- 
marks, the latter causes the flags to be removed. 

163. The leader is now directed to complete his recon- 
naissance of the position, to occupy it with his unit, and to issue 
his fire order — all this under the assumption that his mission 
requires this target to be taken under fire. The instructor may 
add further conditions to the problem, such as, for example, that 
the fire must be opened without delay ; that the position is or is 
not under hostile fife ; that the enemy's air scouts have probably 
marked his position and identified his machine-gun unit as such ; 
that the enemy is known to have artillery observers at X — , 
from which point this position is readily discernible, etc. 

164. The leader makes such further reconnaissance as he 
deems necessary and then brings his unit to the position. The 
unit, in this exercise, consists only of those individuals who 
constitute th,e machinery of command that brings the will of the 
leader to the gunner ; i. e., platoon leaders, squad leaders, gun- 
ners, range takers, guides, agents, etc. 

In a word, the gun squads, except the leaders and gunners, 
are not used. 

165. The leader then issues his fire order in a manner that 
would be feasible under the assumed conditions of the problem. 

Each subordinate leader in turn issues his fire order in a 
similar manner. 

When the fire orders have been issued, each leader and gun- 
ner (by the use of the aiming tripod; see par. 166) indicates 
what he believes to be the limits of the objective or of the frac- 
tion of the objective upon which he has been ordered to direct 



MACHINE-GUN FIRING MANUAL. 167 

his fire. Each also makes a written memorandum as to the ele- 
vation to be used, this elevation being the one he would use in 
compliance with his orders as he understood them. 

This being done, the instructor causes the flags again to be 
displayed at the target, verifies the sighting of the aiming tri- 
pods, checks the elevations used with the true range to the 
objective, and then gives a critique on the execution of the 
exercise. 

166. The aiming tripod is made as follows : Referring to 
plate 62, figure 1-A, the base AB and the arms DE and FG are 
made of hardwood. They are each about \ inch square in cross 
section and about 10 inches in length. 

At its center the base is made fast to the tripod (any camera 
or sketching tripod is satisfactory for this purpose) by a bolt 
and wing nut at C. This joint is made loose enough to permit 
of the base being turned in a horizontal plane without undue 
muscular exertion, but there must still be sufficient friction at 
this point to prevent the base being turned on the tripod by the 
action of a strong wind. 

In like manner the arms are fastened to the ends of the base 
at A and B, the pivot of the arms being about half an inch off 
center to permit of the device being folded as shown in plate 
62, figure 1-B. 

The pointers, HD, IE, JP, and KG, may be made of any 
available pieces of thin sheet metal — zinc, copper, brass, tin, etc. 

The shape and size of these pointers, as cut from the flat 
metal sheet, are as shown in plate 62, figure 1-C. This piece 
is then bent in the shape shown in figure 1-D, plate 62. 

These pointers are riveted to the ends of the arms in such 
manner as to permit of their being placed in an upright posi- 
tion for use, plate 62, figure 1-A, or folded down for packing 
or transportation, plate 62, figure 1-B. 

In use, the tripod is set up with the base approximately per- 
pendicular to the line of fire. When the leader or gunner has 
received his fire order, he decides upon what he believes to be 



168 



MACHINE-GUN FIRING MANUAL. 




Fig. la. 




.A. 






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f 


r 


o 






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Fig.lc. 



Plate 59. 



MACHINE-GUN FIRING MANUAL. 169 

the location of his target and then, using the pointers as front 
and rear sights, directs the arm DE at the point which marks 
the right flank of his particular fraction of the objective, 
while the arm FG is similarly directed at the left flank. 

In judging the execution of any particular exercise the in- 
structor takes into account the probable material effect of the 
fire, assuming it to have been carried out in strict compliance 
with the fire order. 

Errors in the determination of the range are first considered, 
and the probable reduction in accuracy may be found by refer- 
ence to the following table; 



170 



MACHINE-GUN FIRING MANUAL. 



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MACHINE-GUN FIRING MANUAL. 171 

The figures in the body of the table show, in theory, the prob- 
able number of hits that would be obtained for any given esti- 
mate of the range and for any given error in that estimate. 
This is on the assumption that 100 hits will be obtained when 
there is no error in the determination of the range. 

For example, assume a true range of 950 yards to have been 
determined as 1,000. The error is 50 yards. What is the effect 
of this error? 

In the column headed " Estimate " find the amount corre- 
sponding to the estimated range (1,000). Follow this line to 
the right until entering the column corresponding to the error 
(50). Here will be found the figure 59. This figure 59 indi- 
cates that for every 100. hits that would have been obtained 
with the correct range but 59 hits would have been obtained 
with this particular error. 

108. It is not sufficient for the instructor to state merely 
that the range is in error by a certain amount. He must ob- 
serve the manner in which the range was determined ; decide 
whether this method would have been practicable under the 
assumed conditions ; point out the possible or probable causes of 
error ; show how these errors may be eliminated or at least 
reduced in amount ; and state whether the error is or is not 
excessive. 

The instructor next turns his attention to the manner in 
which the target has been designated and to the precision of 
direction and control resulting from this designation. 

169. The instructor's conclusions as to the correctness or 
incorrectness of the designation are based on his own observa- 
tion of the manner in which the leader and his subordinates 
issue their fire orders. The precision of fire attained by the 
order is shown by the aiming tripod. 

Referring to plate 63, let XY be the line of targets and A and 
B be the flags marking the flanks of the particular fraction of 
that line at which fire is to be directed. Let G represent the 
position of the gunner or leader, and the line Ga and Gb repre- 



172 MACHINE-GUN FIRING MANUAL. 

sent the two lines of aim as shown by the arms of the aiming 
tripod. 

Case A shows that the designation and the understanding of 
said designation were perfect, the arms of the aiming tripod 
pointing with precision at the flanks of the target. 

Cases B and C show that the designation or the understand- 
ing of it (the instructor determines by observation whether the 
error lies with the leader or the subordinate) is lacking in pre- 
cision to such an extent as to reduce the effect of the fire by 
one-half; in case B because twice the allotted front is covered 
and hence the assigned target receives but half of the volume 
of fire that should have been directed upon it ; in case C but 
half of the target is covered with fire. 

In case D no credit whatever can be allowed for designation, 
as there is no portion of the target covered with fire. 

By showing how the effect of fire is reduced by the combined 
errors in range and designation, the instructor may give a forci- 
ble demonstration of the fact that the best marksmanship is of 
no avail if acting under the direction of a faulty fire order. 

Take case B for example, and assume that the true range of 
800 yards was estimated at 900 yards. From the table in para- 
graph 167 it is found that this error will reduce the hits from 
100 to 16. As only half of the fire is directed at the target 
this 16 hits would also be reduced by one-half. Hence good 
marksmen, who are capable of making 100 hits on this target, if 
properly directed, make only 8 hits because of the errors of their 
leaders. 

This exercise may be varied in several ways. 

One variation would be to point out the target to the leader 
and then require him to occupy a position several hundred yards 
nearer the objective and there issue his fire order. 

A second variation would be similar to the first except that 
the new position would be well off to one flank as well as to the 
front. 

Both of these might be varied by having the subordinate lead- 
ers shown the target at the first position and then, when the 



MACHINE-GUN FIRING MANUAL. 



173 



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174 MACHINE-GUN FIRING MANUAL. 

second position was reached, to require that the aiming tripods 
be sighted and firing data be communicated by signal alone — 
this under the assumption that the unit has come under a hostile 
fire from the target which makes it impossible to hear the voice. 

Though it would be unusual for a superior commander to use 
a map for the purpose of assigning an objective to so small a 
unit as a company, it is still possible to conceive of situations in 
which such a procedure might be necessary. For this reason a 
further variation of this exercise is suggested in which the in- 
structor uses a map for the purpose of informing the leader as 
to his firing position and his target. The leader occupies the 
position with his unit and issues his fire order without reference 
to the map. 

170. Drill exercises of this general character will serve for 
preparation for rencontre problems, problems in supporting an 
attack, problems in defense and in rear guard and delaying 
actions. 

Preparation for combat problems in trench warfare, night 
firing, and firing at aeroplanes is largely a question of technique. 
The targets, when they appear, will be perfectly self-evident, 
and their fleeting nature will require fire to be opened with a 
maximum of speed and a minimum of orders. 

Note, however, that direct fire at aeroplanes will have no re- 
sult ivhatever and that the data for sight setting and point of 
aim ahead of the flier must be worked out for the gunners before 
fire can be opened with any prospect of success. 

Where the guns or target or both are masked, the firing should, 
as a rule, be done by company, and the preparatory training for 
it will be wholly technical, as far as the gun squads and platoons 
are concerned. The captain alone is responsible for the tactical 
decisions, for the preparation of firing data to be given to the 
gunners for observation of the effect of the fire and the resulting 
change in his fire data. The guns have an arbitrary aiming 
point and an arbitrary elevation and deflection, the target itself 
being invisible to the gunners. 



MACHINE-GUN FIRING MANUAL. 175 

CHAPTER III. 
THE CONDUCT OF FIELD-FIRING EXERCISES. 

171. Range Officials. — All field-firing exercises for ma- 
chine-gun units are held under the general supervision of the 
commanding officer. 

To assist him in these duties the commanding officer may 
detail the following range officials : 

A director of machine-gun practice; 
An umpire or umpires ; 
A range officer ; and 
A recorder. 

In small commands it will be possible to combine the functions 
of director and umpire in the person of a single officer. 

In large commands, several umpires may be required. 

When practicable the director should be senior to all other 
range officials, and both the director and the umpire should be 
senior to any officer participating in the execution of the exer- 
cise. 

The duties of officers are given under the subject of Range 
Regulations (pars. 275-279). 

172. In the conduct of field-firing exercises the umpire should 
take care to present the situation with as much semblance of 
reality as is possible. Only such information is given to the 
troop leader as he naturally would have under the assumed 
conditions. Care should be taken, on the other hand, to avoid 
the withholding of any information that naturally would have 
come to the knowledge of the troops in the course of the action. 

It may be advantageous to have an assistant umpire observe 
the conduct of the troops from the .viewpoint of the enemy, the 
result of his observations to be included in the critique. 

In the earlier stages of training the value of the instruction 
may be enhanced by stopping the exercise and commenting upon 



176 MACHINE-GUN FIRING MANUAL. 

errors at the time they are made. In like manner an umpire 
may correct a wild estimate of the range in order that the 
instructional value of the exercise in other respects may not 
be lost. 

It is only in the earlier stages of training, however, that such 
procedure is admissible. At this time the exercises are solely 
for the purpose of instruction. It is only during the later 
stages of training that they partake of the nature of tests and, 
when this point is reached, the umpire interferes as little as 
possible during the progress of the exercise, the leader being 
allowed to solve the problem in his own way, and being re- 
quired to abide by his own mistakes and those of his sub- 
ordinates. 

173. The Basis of Judgment. — In order to pass intelligent 
judgment upon the solution of a fire problem, there must be 
standards with which the performance in question may be com- 
pared. 

The decision of the umpire as to the amount of credit to 
attach to any given solution of a technical problem must follow 
as a logical result of the answer to his self-directed query 
" Had these hypothetical conditions been real, is it probable or 
improbable that the solution I have just witnessed would have 
accomplished the mission? " More definite guidance is unneces- 
sary for the trained umpire, nor would it in any manner make 
up for the deficiencies of an untrained one. 

Without doubt there are many shades of proficiency or de- 
ficiency between unqualified success and flat failure. These 
must be taken into account by the umpire. For example, he 
might state in his critique, " It seems entirely probable that 
your mission would have been accomplished, but your method 
of attack would have been unnecessarily costly. You directed 
fire on the enemy at a rate which was but little greater than 
that which they were directing upon you. Considering troops 
of equal morale, your higher rate of fire doubtless would have 
obtained fire superiority in the end, but at the expense of much 
time, much ammunition, and many casualties.*' 



MACHINE-GUN FIRING MANUAL. 177 

174. In judging of the solution of a tactical problem which 
includes the firing of ball cartridges, the umpire must take care 
to differentiate between failures which result from a non- 
observance of tactical principles and those which result from a 
lack of technical knowledge or skill, and he should indicate 
them thus in his critique. In like manner he should call atten- 
tion to these two factors when contributing to success. 

The umpire's guide as to the tactical employment of the 
machine gun is that part of the text of the Field Service Regu- 
lations, the Drill Regulations of the infantry and cavalry arms, 
and the Machine Gun Drill Regulations which deals with the 
tactical employment of this weapon. 

175. In judging of the technical knowledge and skill of the 
participants, the umpire has two phases to consider. First, that 
which deals with the commanding officer's part in the solution 
of the problem, and, second, that which deals with the machine- 
gun commander's part in the problem. 

In judging of the commanding officer's share in the solution 
of the problem, the umpire considers — 

1. Was the mission such that the decision to use these par- 
ticular guns, as an agency for its accomplishment, an admissible 
procedure ? # If not, what other troops or arms were available 
that were better suited to the purpose? 

2. Were a sufficient number of guns used for the accomplish- 
ment of the mission? If not, was it due to an error in judgment 
on the part of the commander or to the conditions imposed by 
the problem? If due to an error in judgment, is that error due 
to the conditions of the problem or is it due to lack of training? 

3. To what extent did the commanding officer's share in the 
solution of this problem contribute to success or failure? 

In considering the machine-gun commander's share in the 
solution of the problem, the umpire employs, as a standard of 
comparison, the results that might be expected from a well- 
trained organization having at its disposal the same number of 
106191°— 17 12 



178 MACHINE-GUN FIRING MANUAL. 

guns that were made available in this problem by the order of 
the commanding officer. 

Thus, an umpire's decision might take the following form : 

" The mission was not accomplished because of the failure of 
the commanding officer to assign a sufficient number of machine 
guns to this task (or because he assigned machine guns to a 
task properly belonging to riflemen, or because he assigned to 
the light gun a task that could only be accomplished by heavy 
guns). The actual results obtained by the guns, however, were 
in excess of what might be expected from a well-trained or- 
ganization acting under similar circumstances." 

Or, in another case : 

"The mission was accomplished, but about twice as many 
guns as necessary were assigned to the task. The actual results 
obtained by the guns, however, were far below what might be 
expected from a well-trained organization acting under similar 
conditions." 

The material effect of fire is shown by the number and the 
distribution of hits upon the recording area of the target. To 
judge of its psychological or tactical effect, the umpire must 
take into account the length of time required to obtain a given 
material effect. 

176. The judgment of the effect of fire as an agency for the 
accomplishment of a given mission will depend upon the nature 
of the problem. In the employment of machine guns for repuls- 
ing an assault, for example, the criterion would be the number 
of casualties produced during the enemy's charge. In covering 
an assault, on the other hand, the measure of efficiency is, first, 
the rate of impact of the fire directed upon the enemy's trenches, 
and, second, when the sheaf has been raised in order to avoid 
casualties among our own troops, the percentage of casualties 
among enemy reinforcements moving forward to the fire trench. 

Judgment of the number of casualties produced is secured 
with the aid of the two following tables : 



MACHINE-GUN FIRING MANUAL. 

Umpire's reference table. 
PRONE FIGURES. 



179 

















Time (minutes). 






Range 
























(yards). 


i 


i 


3 


1 


li 


2 


2| 


3 


3§ 


4 


5 


6 


10 


15 


20 


25 


30 


200 


42 

39 


66 
63 


80 
78 


89 

87 


96 
55 


99 


99 
99 


100 
100 








































300 


30 
30 


52 

51 


66 
65 


77 
76 


89 
88 


94 
24 


98 

38 


99 

99 


99 

55 


99 
99 


100 
100 




























400 


23 

23 


41 

41 


55 

55 


66 
66 


80 
80 


88 
88 


93 
93 


96 

3£ 


98 
98 


99 
99 


99 

99 


100 
100 
























500 


19 

16 


34 

29 


46 
40 


57 
50 


71 
65 


81 

75 


88 
82 


92 

87 


95 
Pi 


97 

34 


99 

38 


99 
99 


100 
100 




















600 


15 
12 
9 

7 


28 
22 
17 
13 


38 
31 
25 
19 


48 
40 
32 
25 


62 
53 
44 
35 


73 
63 
54 

44 


80 
72 
62 
51 


86 

78 
68 
58 


90 

83 
74' 
64 


92 
87 
79 

68 


95 
92 

85 
76 


98 
95 
90 

82 


100 

99 
98 
94 










700 


100 
99 
99 








800 


100 
99 






900 


100 




1,000... 


5 


10 


15 


19 


27 


35 


41 


47 


54 


57 


66 


72 


88 


96 


99 


99 


100 



180 



MACHINE-GUN FIRING MANUAL. 
Umpire's reference table — Continued. 

KNEELING FIGURES. 



Range 
(yards). 












Time 


minutes). 


i 


i 

2 


3 


1 


1| 


2 


2| 


3 


35 


4 


5 


6 


10 


15 


200 


60 
59 


84 
83 


93 
93 


98 
98 


99 

99 


100 

100 


































300 


48 
47 


73 

72 


86 
85 


93 

92 


99 
0S 


99 
99 


100 

100 






























400 


39 
36 


63 

59 


77 
74 


86 
84 


95 
93 


99 
98 


99 


99 

99 


100 
100 






















500 


32 

n 


54 

41 


69 
55 


79 
00 


90 

SO 


96 


98 
93 


99 
96 


99 

98 


100 

99 










99 


100 






600 
700 


26 
21 


46 

38 


60 
51 


70 
61 


84" 
76 


91 

85 


95 
91 


99 

94 


99 
97 


99 
98 


100 

99 








99 


I 
100 


800 


17 


30 


42 


52 


66 


77 


84 


89 


92 


95 


'98 


99 


100 


900 


13 


24 


34 


42 


56 


67 


75 


81 


85 


89 


94 


97 


99 100 


1,000 


10 


18 


26 


33 


46 


56 


64 


71 


76 


80 


87 


91 


99 100 



Note. — Amounts in body of table indicate the percentages of figures that should 
be struck . Those in italic indicate ' ' battle sight . ' ' 



MACHINE-GUN FIRING MANUAL. 
177. Machine-gun umpire's table. 



181 





Equiva- 


Range 


lent fire 


(yards). 


power in 




terras of 




rinement. 


200 


15 


400 


13 


600 


22 


800 


29 


1,000 


40 



Though based upon mathematical calculation, the standard 
expressed in these tables must be quite flexible in its applica- 
tion. The figures in the tables are merely averages obtained 
from the firing of many hundreds of cartridges and hence rep- 
resent nothing more than the probable material effect to be ex- 
pected provided the cone of fire under consideration is similar 
to the average cone. Furthermore, these figures are based on 
the assumption that the center of impact lies exactly at t.ie 
center of the target and that the distribution is perfect. Plainly 
this is a theoretical ideal which rarely if ever will be attained in 
practice. Thus, should the actual result be a little less or even a 
little more than that specified in the table this would indicate 
neither deficiency nor a remarkable proficiency, but merely that 
the actual result was a somewhat close approximation to the 
probable average. 

If the tables are used merely as a guide, they will be used 
correctly. They will be used incorrectly if the figures in the 
table be taken as indicating a sharp line of demarcation between 
proficiency and deficiency. 



182 MACHINE-GUN FIRING MANUAL. 

178. The machine-gun umpire's table is based on the as- 
sumption that the rate of fire of the machine gun is 100 shots 
per minute. Should the actual or correct rate be other than 100, 
then the figures in the second column would vary directly as 
the rate, i. e., if the rate were 200 shots per minute, then the 
figures in the second column would be doubled ; if 250 shots per 
minute, then they would be multiplied by 2J, etc. 

179. These tw T o tables, the umpire's reference table and the 
machine-gun umpire's table, are used in conjunction in the fol- 
lowing manner. An example will best illustrate their use. 

Assume a machine gun to have been firing at a plainly visible 
target composed of 100 kneeling figures occupying a front of 100 
yards. The target is 300 yards distant and the firing lasted 
for one minute. Fifty figures were struck. Was this fire 
satisfactory or not? 

First, consult the umpire's reference table. What is sought 
is the number of riflemen who, in firing at this target for one 
minute, probably would have struck 50 per cent of the figures 
in the target — the percentage struck by the machine gun. On 
the line of the 300-yard range and in the i-minute column is 
found the amount 48, which is a close enough approximation to 
50 for the purpose of this comparison. This 48 indicates that 
100 riflemen firing at these 100 figures probably would strike 
48 per cent of them in one-fourth of a minute. 

The figure sought is now found by the proportion — 

The actual duration of the fire in minutes 1 

is to 

The time required for a number of riflemen, : 
equal to the number of figures in the target, to 

produce the same result as the gun i 

as : : 
A number of riflemen equal to the number of 

figures in the target . 100 

is to : 

The number of riflemen sought 25 



MACHINE-GTJN FIRING MANUAL. 18$ 

That is to say, 25 riflemen, firing at this target for 1 minute, 
probably would strike about 50 figures, or the gun has shown a 
fire power equivalent to 25 rifles. 

To determine the credit to attach to this performance, the 
machine-gun umpire's table is consulted. The umpire decides 
that the rate of fire should have been 150 shots per minute and 
hence, from the table, it is seen that the gun should show a 
theoretical value of about 24 rifles. The umpire would decide 
quite correctly that this firing indicated proficiency in technical 
skill. 

In this same example, had there been 2 guns firing, then they 
would have shown a value of 121 rifles each, while 4 guns would 
have been worth 6i rifles each, assuming, of course, that the 
firing in each case resulted in 50 figures being struck. A judg- 
ment of " lacking in technical skill " might or might not be 
correct in the case of the two guns with a value of 12^ rifles 
each, but probably would be justified in the case of the four 
guns with a value of 6| rifles each. 

180. In judging of the casualties that would be produced 
among troops moving through a given beaten zone — as, for ex- 
ample, the sheaf of fire directed in rear of a fire trench to pre- 
vent the forward movement of reinforcements, the umpire may 
assume that any target moving through the beaten zone at a 
uniform speed will receive half as many hits as it would have 
received had it remained stationary for the same length of time 
at the center of impact. For example, assume a beaten zone 100 
yards in depth and that a target passes through that zone at a 
uniform speed in 20 seconds. Then that target will receive half 
as many hits as it would have received had that same sheaf been 
directed upon it with perfect adjustment for 20 seconds. 

181. The judgment as to rates of impact is based on the 
following : 

To obtain, on a single yard of front, a rate of impact of 1 hit 
per minute, the following rates of fire must be maintained. Per- 
fect adjustment is assumed. 



184 



MACHINE-GUN FIRING MANUAL. 



Range. 


Kind of target. 


Head. 


Prone. 


Kneeling. 


Standing . 


Horse. 


200 


14.90 
22.50 
30. SO 
43. 63 
51.00 


3.15 
5.31 
7.12 
9.36 
• 11. 93 


2.45 
3.20 
4.02 
5.03 
6.36 


2.95 
3.18 
3.64 
4.33 
5.27 


1.41 


400 


1.42 


600... 


1.51 


800 


1.68 


1,000 


1.95 







For any given rate of fire the rate of impact will vary inversely 
as the size of the target. Thus, with the kneeling targets at 
400, yards and a rate of fire of 3.2, the rate of impact would be 
one-half if the target were 2 yards wide, and one-fourth if the 
target were 4 yards wide. 

To maintain a given rate of impact the rate of fire must vary 
directly as the size of the target. Thus, to maintain a rate of 
impact of 1 on a target composed of prone figures on a front 
of 100 yards and at a range of 600 yards the rate of fire must 
be 712. On the same front head targets at 400 yards would 
require a rate of fire of 2,250, and mounted figures at 1,000 yards 
a rate of fire of 195 in order to maintain the rate of impact at 1. 

For any given target the rate of impact will vary directly as 
the rate of fire. If it is desired to double the rate of impact, 
then the rate of fire must be doubled, etc. Thus, considering 
that it was desired to maintain a rate of impact of 10 on stand- 
ing targets at 800 yards, then the required rate of fire would be 
43.3 for each yard of front occupied by the objective, e. g., if the 
target had a frontage of 10 yards, then the required rate of 
fire would be 433 ; if it occupied a front of 100 yards, the required 
rate of fire would 4,330, etc. 

182. The percentage of casualties depends upon the volume 
of impact as shown in the following table. In this table the 
column H (hits) gives the volume of impact — the average num- 



MACHINE-GUN FIRING MANUAL. 



185 



ber of hits per unit of front; and the column D (distribution) 
indicates the percentage of units of front that should be struck 
with an evenly distributed fire. 

It will be noted that when the volume of impact reaches 3 the 
percentage of casualties is 95 per cent, and that a further in- 
crease of 100 per cent in the volume of impact (increasing it 
to 6) results in an increase of only about 5 per cent in casualties. 



H. 


D. 


H 


P. 


H. 


D. 


H. 


D. 


0.01 


1.0 


0.31 


26.7 


0.61 


45.7 


0.91 


59.8 


0.02 


2.0 


0.32 


27.4 


0.62 


46.2 


0.92 


60.2 


0.03 


3.0 


0.33 


28.1 


0.63 


46.7 


0.93 


60.6 


0.04 


3.9 


0.34 


28.8 


0.64 


47.2 


0.94 


60.9 


0.05 


4.9 


0.35 


29.5 


0.65 


47.8 


0.95 


61.3 


0.06 


5.8 


0.36 


30.2 


0.66 


48.3 


0.96 


61.7 


0.07 


6.8 


0.37 


30.9 


0.67 


48.9 


0.97 


62.1 


0.08 


7.7 


0.38 


31.6 


0.68 


49.4 


0.98 


62.5 


0.09 


8.6 


0.39 


32.3 


0.69 


49.8 


0.99 


62.8 


0.10 


9.5 


0.40 


32.9 


0.70 


50.3 


1.00 


63.2 


0.11 


10.6 


0.41 


33.6 


0.71 


50.8 


1.02 


63.9 


0.12 


11.3 


0.42 


34.3 


0.72 


51.3 


1.04 


64.7 


0.13 


12.2 


0.43 


34.9 


0.73 


51.8 


1.06 


65.4 


0.14 


13.1 


0.44 


35.6 


0.74 


52.3 


1.08 


66.0 


0.15 


13.9 


0.45 


36.2 


0.75 


52.8 


1.10 


66.7 


0.16 


14.8 


0.46 


36.9 


0.76 


53.2 


1.12 


67.4 


0. 17 


15.6 


0.47 


37.5 


0.77 


53.7 


1.14 


68.0 


0.18 


16.5 


0.48 


38.1 


0.78 


54.2 


1.16 


68.6 


0.19 


17.3 


0.49 


38.7 


.0.79 


54.6 


1.18 


69.3 


0.20 


18.1 


0.50 


39.4 


0.80 


55.0 


1.20 


69.9 


0.21 


18.9 


0.51 


40.0 


0.81 


55.5 


1.22 


70.5 


0.22 


19.7 


0.52 


40.5 


0.82 


56.0 


1.24 


71.1 


0.23 


20.5 


0.53 


41.1 


0.83 


56.4 


1.26 


71.6 


0.24 


21.3 


0.54 


41.7 


0.84 


56.8 


1.28 


72.2 


0.25 


22.1 


0.55 


42.3 


0.85 


57.3 


1.30 


72.7 


0.26 


22 9 


Of 56 


42.9 


0.86 


57.7 


1.32 


73.3 


0.27 


23.7 


0.57 


43.4 


0.87 


58.1 


1.34 


73.8 


0.28 


24.4 


0.58 


44.0 


0.88 


58.5 


1.36 


74.3 


0.29 


25.2 


0.59 


44.6 


0.89 


58.9 


1.38 


74.8 


0.30 


26.0 


0.60 


45.1 


0.90 


59.3 


1.40 


75.3 



186 



MACHINE-GUN FIRING MANUAL. 



H. 


D. 


H. 


D. 


H. 


D. 


H. 


D. 


1.42 
1.44 
1.46 
1.48 
1.50 
1.52 
1.54 
1.56 
1.58 
1.60 

1.62 
1.64 
1.66 
1.68 
1.70 
1.72 
1.74 
1.76 
1.78 
1.80 


75.8 
76.3 
76.8 
77.2 
77.7 
78.1 
78.6 
79.0 
79.4 
79.8 

80.2 
80.6 
81.0 
81.4 
81.7 
82.1 
82.4 
82.8 
83.1 
83.5 


1 82 
1.84 
1.86 
1.88 
1.90 
1.92 
1.94 
1.96 
1.98 
2.00 

2.05 
2.10 
2.15 
2.20 
2.25 
2.30 
2.35 
2.40 
2.45 
2.50 


83.8 
84.1 
84.4 
84.7 
85.0 
85.3 
85.6 
85.9 
86.2 
86.5 

87.1 
87.7 
88.4 
88.9 
89.5 
90.0 
90.4 
90.9 
91.4 
91.8 


2.55 
2.60 


92.2 
92.6 


4.50 
5.00 


99.0 
99.3 


2.65 
2.70 


92.9 
93.3 


5.50 
6.00 


99.5 

99.8 


2.75 

1 2.80 
2.85 
2.90 


93.6 
93.9 
94.2 
94.5 






















2 95 
3.00 


94.8 
95.0 














3.25 
3.50 


96.4 

97.8 














3.75 
4.00 


98.3 

98.7 























If every figure in the target is hit H times on the average, 
then from the table, D per cent of the figures will be hit. 

It may be assumed,, therefore, that, in theory at least, a vol- 
ume of impact of 3 will meet the maximum requirements in 
the production of casualties. This theory is confirmed by actual 
experience in combat. 



CHAPTER IV. 

THE CRITIQUE OF FIELD-FIRING EXERCISES. 

183. The critique is a statement by the umpire in which 
he compares in detail a given solution of a problem with a solu- 
tion that might be expected from a thoroughly trained organi- 
zation acting under similar conditions. 



MACHINE-GUN FIRING MANUAL. 187 

The basis of all good instruction is intelligent, tactful, and 
constructive criticism. This should be the aim of the critique. 

The illustration of principles and their intelligent criticism 
depends solely upon the ingenuity and. alertness of the umpire, 
who must make the exercises conform to local conditions. 
Otherwise a field firing exercise degenerates into mere practice 
in technique and its tactical significance is lost. 

The umpire should bear in mind that, aside from the practical 
application of abstract principles to concrete cases, the instruc- 
tional value of a field firing exercise lies wholly in the critique. 

184. Much depends upon the personality of the umpire, for 
it often will be his duty to call attention to errors and faults 
that may be due to lack of judgment, lack of knowledge, or 
lack of skill, and all this must be done without giving offense 
to his hearers. 

185. The critique should seek to bring to the mind a con- 
ception of what the situation would be were it real instead of 
merely assumed. 

186. Failures properly to apply tactical principles often are 
due to misconceptions as regards modern combat, and it is these 
misconceptions that the critique should seek to eradicate. 

The umpire should not only comment upon faulty procedure 
but should seek also to bestow commendation for a proper appli- 
cation of principles whenever the nature of the case seems to 
warrant it. 

It should not convey the impression that there is one particu- 
lar method of executing the exercise which is the correct 
method. This is only too apt to lead to the adoption of fixed 
forms, and this tending to destroy initiative should be studiously 
avoided. 

187. The critique is best given on the ground immediately 
after the conclusion of the exercise. When required for record, 
a synopsis only is written. 

In the critique an umpire should be careful to differentiate 
between statements of opinion and statements of fact, principle, 
or experience. 



188 MACHINE-GUN FIRING MANUAL. 

The following are some of the points on which an umpire 
might comment : 

Was the mission accomplished? 

If so, what were the causes contributory to success? 
If not, was failure due to any of the following causes : 
The assignment of machine guns to a task that called for 

other weapons ; 
. Premature opening of fire or too long a delay in so doing ; 
Failure to conceal the identity of the guns during the 

advance to the firing position ; 
Inadequate fortification or concealment ; 
Inadequate or faulty reconnaissance ; 
Ambiguous or wrong target designation; 
Faulty determination of ranges ; 
Poor adjustment of fire ; 
Poor observation of fire ; 
Laxity in fire direction and control ; 
Ambiguous or incomplete fire orders ; 
Lack of fire discipline ; 
Poor marksmanship ; 
Malfunction of guns through ignorance of poorly trained 

gun crews ; 
Rate of fire too slow to produce required rate of impact 

or too fast for accuracy ; 
Poor distribution ; 
Insufficient safety angle, the fire resulting in casualties 

among our own troops, etc.? 



CHAPTER V. 

COMBAT PRACTICE— RECORD. 

188. After having had such preliminary training in the 
solution of fire problems as the time available and ammunition 
permits, the organization will be given a record combat prob- 
lem—such problem to involve as many of the essential features 



MACHINE-GUN FIRING MANUAL. 189 

of fire training as the range facilities will admit. An annual 
ammunition allowance of 500 rounds per gun is authorized for 
this problem. 

A very careful record will be kept of this exercise and a 
proper report made to the division commander under paragraph 
293. The organization will not be given a rating on this prob- 
lem, andit'is not to be considered as a test, but is more for the 
purpose of furnishing to higher commanders information regard- 
ing methods and means used in the solution of such problems. 
However, in case any performance appears to be excellent it 
should be noted, as should any other pertinent points that are 
worthy of record. 



PART IV. 



THE THEORY OF FIRE. 



CHAPTER I. 
THE BALLISTIC QUALITIES OF MACHINE GUNS. 

189. The ballistic qualities of machine guns are, for all 
practical purposes, the same as those of the infantry rifle. 

The ballistic data pertaining to the service ammunition is 
found in the Ordnance pamphlet (No. 1923) describing the 
United States magazine rifle, and includes a description of the 
various types of cartridges issued ; tables showing corrections 
for variations in initial velocity, temperature, and barometric 
pressure; the maximum range, powder pressure, energy of re- 
coil, accuracy (deviation only), penetration, and point blank 
danger space ; a table of fire ( angles of elevation and departure, 
angles of fall, time of flight, etc. ) ; a table of ordinates ; a table 
of dangerous spaces ; a table of horizontal deviations ; and 
tables of corrections for given velocities and directions of wind. 

190. Powers and Limitations. — The powers and limitations 
of machine guns may be divided into two general classes — 
physical and psychological. 

The machine gun is both physically and psychologically, poten- 
tially more powerful than a number of rifles producing an equal 
volume of fire, but the limitations upon the fire of machine guns 
are greater than those of a number of rifles capable of producing 
the same fire effect, 
190 



MACHINE-GUN FIRING MANUAL. 191 

A. POWERS. 

191. A. Physical. — (1) The sheaf produced by the fire of 
machine guns is more compact than that of an equal volume of 
rifle fire. 

This is principally due to the fact that the " holding " of the 
firearm is done by the mount and not by the firer, thus eliminat- 
ing many of the personal errors of the latter, such as flinching, 
faulty trigger squeeze, unsteady hold, etc. 

The size of the sheaf of the automatic machine rifle depends 
to a great extent upon the skill of the gunner. It has been 
made (in practice on the target range) and with well-trained 
gunners as small as one-quarter of that of " average rifle shots." 
But all so-called machine rifles that are fired from the shoulder 
are subject to the same human influences as the rifle. These 
influences are reflected in an increased dispersion on the battle 
field. 

The effects of the nervous emotions of the gunner when firing 
with his gun on a standard machine-gun mount, sled, or tripod 
are not transmitted to the gun. Therefore the battle dispersion 
of this type of gun is little if any greater than its peace dis- 
persion. 

It is quite obvious that with proper adjustment of this smaller 
sheaf the fire should be more accurate than that of riflemen, 
i. e., there should be a greater number of hits for any given ex- 
penditure of ammunition. 

This compact sheaf, and the ease with which the fire of sev- 
eral guns may be concentrated upon a single point, makes th'e 
machine gun particularly adapted for use in covering certain 
definite restricted areas, such as bridges, roads, approaches, ob- 
stacles, landings, defiles, etc. 

192. (2) The fire poiver of the machine gun has been vari- 
ously estimated as being equal to that of from SO to 60 riflemen. 

Considering an accurate and properly distributed fire, the 
basis of comparison between machine guns and riflemen is the 



192 MACHINE-GUN FIRING MANUAL. 






rate of fire. The rate of fire of the machine gun depends on 
the type of gun and on the skill of the gun crew, the lowest rate 
being obtained by untrained or semitrained men with an auto- 
matic machine rifle, this rate being from to 40 shots per 
minute per gun, and the highest rate being obtained by expert 
gun crews with a belt-loaded gun of the Maxim type, this rate 
running from 500 to 700 shots per minute per gun. 

193. The rate is not influenced to any marked degree by 
variations in the range. The character of the objective, how- 
ever, has a decided influence upon it. With a broad, deep tar- 
get, such as troops in mass formation, fire may be directed at 
a single aiming point and be practically continuous, whereas 
at a linear target whose elements are separated by wide inter- 
vals fire must be by short bursts, with a change of aiming point 
for each burst. 

For purposes of comparison with rifle fire it may be said, 
then, that for any given target the rate of fire of the machine 
gun is practically constant irrespective of the range, while that 
of riflemen decreases as the range increases, i. e., they fire 10 
shots per minute at the shorter ranges and 5 shots per minute 
at the longer ones. Assuming, then, that the average rate of 
fire of the machine gun runs from 20 to 600 shots per gun per 
minute, it follows that to produce an equal rate of fire it would 
take 2 to 60 riflemen at the shorter ranges and from 4 to 120 
riflemen at the longer ranges for each machine gun employed. 

This concentration of fire power in the hands of a single 
man makes the machine gun a desirable weapon to use as a 
substitute for riflemen in cases where the front is so restricted 
as to prevent sufficient riflemen being deployed to produce the 
required rate of fire. Such cases would be in salients, re- 
entrants, and defiles. 

With the power of from 30 to 60 rifles in the hand of a single 
individual, fire control and fire direction are quite simple as 
compared with the difficult problem of infantry. The move- 
ment of the sheaf is also much more responsive to the will of 
the leader, and the piece may be loaded and laid to cover a 



MACHINE-GUN FIRING MANUAL. 193 

given area, either by day or night, and then, by keeping but a 
single man on the alert, maybe held indefinitely as a reserve force 
to be applied instantly when the necessity arises by the mere 
pressure of a finger. To accomplish a like result from 30 to 60 
riflemen must be kept constantly on the alert, and even then 
under the conditions of night firing their fire would not be 
as dependable as that of the gun. 

194. (3) A loss of machine-gun personnel does not neces- 
sarily mean a loss of fire power, for, with the gun in position 
and well supplied with ammunition, fire may continue undimin- 
ished so long as there remains a single man capable of operating 
the piece. 

The vulnerability of the personnel may be said, in general 
terms, to be the same as that of infantry, but with every 
casualty the infantry lose fire power unless the losses in the 
firing line are replaced by supports, whereas a machine-gun unit 
may suffer losses that would stagger an Infantry organization 
and yet continue in the fight with undiminished fire power. 

The vulnerability of a machine-gun crew may be compared 
to that of a like number of riflemen ; nevertheless the target 
presented to the enemy is so small that even while fire is in 
progress it will prove difficult to locate, provided there is proper 
concealment, and when located it will demand a great expendi- 
ture of ammunition in order to silence it. This latter condition 
is especially true of guns provided with shields. 

195. (4) The mobility of the machine gun is that of the 
Infantry or Cavalry with which it operates. 

The machine gun, with its pack transportation, can maneuver 
or march with Infantry or Cavalry, and on entering the zone 
of hostile fire it can be carried by its personnel over any ter- 
rain accessible to Infantry. 

The utility of the machine gun from the viewpoint of mobility 
depends not so much upon the ease with which it can be car- 
ried by its pack or wheeled transport as upon the facility with 
which it can be moved from place to place by its dismounted 
106191°— 17 13 



194 MACHINE-GUN FIRING MANUAL. 

personnel when operating within the zone of hostile fire. For 
the latter is a prime essential, while the former is merely a 
question of selecting that type of transportation suitable for 
making progress over the country to be traversed and then 
adapting that type to carry the special machine-gun equipment. 

Thus the mobility of machine guns presents two phases — 
their mobility in combat and their mobility on the march or in 
maneuver. 

Mobility in combat depends primarily upon the type of mount 
and combat equipment used with the gun, as practically all 
machine guns have been reduced below 30 pounds in weight. 

Mounts and other combat equipment are divided roughly into 
two classes — those that must be carried and those that may be 
dragged. Of the former are the muzzle rest and tripod types of 
mount, and of the latter the sledge of the Germans and the low- 
wheeled mount of the Russians. 

196. The mobility of the machine gun on the march or in 
maneuver should be suitable to the task it has to perform. With 
guns that are to act as strictly regimental auxiliaries, the prob- 
lem is well solved by pack transportation, as all that is de- 
manded of the guns is merely to keep pace with the regiment. 
With the guns that are attached to higher units than the regi- 
ment, animal draft or motor transportation would seem to be 
essential. 

197. B. Psychological. — The psychological or moral power 
of the machine gun lies in its prestige as a deadly weapon, the 
sound of its fire, its ability to produce many casualties in a short 
space of time, and in the fact that its force may be withheld 
until the crisis of the action and then applied unexpectedly or 
as a surprise. 

B. LIMITATIONS. 

198. A. Physical. — (1) The compact cone of the machine 
gun demands precise adjustment, and it can be directed at but 
a single point at a time. 

The fire of a machine gun, though equal to that of many 
riflemen, is capable of being directed at but a single point at a 



MACHINE-GUN FIRING MANUAL. 195 

time, whereas that of a number of rifles producing an equal 
volume may be concentrated to cover a single point or may be 
distributed so as to cover simultaneously every point in a given 
area. In this connection there is also the danger, with poorly 
trained men, that in the excitement of combat an undue amount 
of fire will be directed at a single point when the tactical situa- 
tion demands an even distribution of fire to cover an extended 
line or area. 

The compactness of the machine-gun sheaf demands an ex- 
treme nicety of adjustment of fire in order that material results 
may be obtained commensurate with the expenditure of ammuni- 
tion. With this peculiar weapon correct adjustment means not 
only accurate range finding, but also an intimate knowledge of 
the individuality or the " equation " of each particular gun. 
These difficulties of adjustment, as well as those of observation 
of fire at long ranges, preclude the probability of effective fire 
by machine guns at ranges exceeding 1,200 to 1,500 yards. This 
does not mean that these guns are never to be used beyond these 
ranges. There are instances where these guns have been used 
with great effect at ranges as great as 2,500 yards, but the con- 
ditions were particularly advantageous both as to the size and 
immobility of the target and as to facility of observation— visi- 
bility of target and of impact. 

109. (2) Machine guns are not suited for continuous par- 
ticipation in a prolonged fire fight. 

This comes not only from the fact that they will be promptly 
overwhelmed by hostile fire when once they disclose their posi- 
tion, but also from the fact that frequent pauses must be made 
in the firing in order that the mechanism of the pieces may be 
cooled and oiled, and that jams may be reduced. 

The position of the gun may be disclosed by the peculiar sound 
of automatic firing and, with water-cooled guns, by the escape 
of steam. Once located, the guns at once become the target for 
all hostile artillery and infantry capable of firing upon them. 
For this reason it is not only essential that there be concealment 



196 MACHINE-GUN FIRING MANUAL. 

and defilade for the guns, but also that usually they be located 
elsewhere than in the infantry firing line. 

By having the guns away from the infantry line fire directed 
on the former will be withdrawn from the latter, and thus will 
prove an additional aid to the advance of the infantry soldier. 

The escaping steam of water-cooled guns must be condensed. 

200. (3) Machine guns are more vulnerable in many ways 
than Infantry or Cavalry. 

The mechanism of the machine gun is delicate and may be 
disabled by a single well-placed hostile bullet. In the difficulties 
of supply that are incident to any campaign there is apt to be a 
scarcity of cleaning and lubricating material that will do much 
toward increasing the frequency and seriousness of jams. The 
guns may even become disabled from this cause alone. 

The difficulties of ammunition supply in the attack render it 
improbable that any particular machine-gun unit would be able 
to meet the exigencies of but a single crisis in the action without 
a renewal of its ammunition supply. 

201. The machine-gun organization with its animal trans- 
port is particularly vulnerable and helpless on the march. Its 
security at such times must be provided for by detachments of 
Infantry or Cavalry. 

202. (4) The mobility of a machine-gun organization is 
readily destroyed by casualties. 

The mobility of a machine-gun organization on the march or 
in maneuver depends on the condition of its means of transpor- 
tation. If these means become disabled, the weight of the equip- 
ment is so great that the personnel can not carry it and keep 
pace with the troops with which the guns are marching. 

The mobility of the gun in combat depends upon the ability 
of the personnel to move the equipment and the ammunition 
supply. Obviously, casualties first reduce the ammunition sup- 
ply and finally render the equipment immobile. 

203. B. Psychological. — Psychologically, the machine gun 
is lacking in the threat of personal encounter with an armed 
enemy. 



MACHINE-GUN FIRING MANUAL. 



197 



There is no threat or apprehension of personal combat with 
the bayonet, as the power of the machine gun lies in fire action 
alone. 

There is nothing so harmless as a disabled machine gun. 



204. 



C. SUMMARY. 



Poivers. 



Limitations. 



Smaller sheaf fire more accu- 
rate than Infantry and more 
easily controlled. The bal- 
listic properties are the same 
as those of the rifle. 

Each gun represents an in- 
stantly available reserve of 
fire power equal to from 30 
to 60 rifles. This permits fire 
to be delivered from a re- 
stricted front at a high rate. 

With ammunition at hand, the 
fire power is undiminished 
so long as there remains a 
man unwounded who can op- 
erate the gun. 

Its mobility is such that it can 
operate over any terrain ac- 
cessible to Infantry or to 
Cavalry. 

The moral power of the gun 
lies in its prestige, in the 
sound of its fire, in its sur- 
prise action, and in its ability 
to produce many casualties 
in a short space of time. 



Small sheaf demands precise 
adjustment of fire and can be 
directed at but one point at 
a time. 

Can not be used continuously 
in a prolonged fire fight. 
Ten to fifteen minutes' con- 
tinuous firing is about the 
limit of its opportunity or 
capability at any time. 

The mechanism of the piece is 
delicate and is readily dis- 
abled by hostile fire or by a 
lack of a suitable supply of 
cleaning and lubricating ma- 
terial. 

Heavy losses of personnel de- 
stroy mobility in battle ; 
those of pack animals, mo- 
bility in march or maneuver. 

The gun is limited to fire ac- 
tion. There is lacking the 
threat of the bayonet. A 
disabled gun is at once an 
encouragement to the enemy 
and a discouragement to our 
own troops. 



198 MACHINE-GUN FIRING MANUAL. 

CHAPTER II. 
RATES AND VOLUMES AND THEIR RELATION TO EFFECTIVENESS. 

205. Cyclic rate is a term used to express the speed at which 
a gun delivers its fire while operating without interruption. 
This cyclic rate' is expressed in terms of "shots per minute," 
though for the sake of brevity the w r ords "shots per minute" 
often are omitted. For example, should an automatic rifle fire 
a strip of 30 cartridges in 3 seconds, and this without pause or 
interruption of any kind, then it is said to develop a cyclic rate 
of 600. 

The cyclic rate is not altered because of malfunctions or 
because of voluntary pauses made by the gunner — only that 
firing being considered which is continuous and without inter- 
ruption. Thus, suppose 10 shots were fired in 1 second and the 
piece then stopped firing because of a jam, the cyclic rate remains 
600. 

; The cyclic rate differs for different types of guns, and in some 
types it is possible to control this rate within rather narrow 
limits by certain modifications in the adjustment of the mecha- 
nism. 

For any given adjustment of the mechanism of a particular 
type of gun, the cyclic rate may be reduced by such causes as 
the accumulation of fouling from continued firing, lack of lubri- 
cation, faulty cleaning, the use of heavy lubricants or the freez- 
ing of the lubricant in cold weather, etc. 

206. The rate of fire of a single gun is the average number 
of shots fired per minute during the time between the first and 
the last shot of any particular firing. In speaking of the rate 
of fire of an organization (company or platoon), it is usual to 
differentiate between the " gun rate," which is the mean of the 
rates- of all the guns, and the "company (or platoon) rate," 
which is the sum of the rates of all the guns. 

For the sake of brevity, rate of fire usually is expressed in 
numerals alone, e. g., " the rate of fire is 200 " means " the rate of 
fire is 200 shots per gun per minute." 



MACHINE-GUN FIRING MANUAL. 199 

The rate of fire that is adaptable to tactical uses usually is 
somewhat less than the cyclic rate, this being clue to the neces- 
sity for pauses in the fire for the purpose of correcting the aim, 
changing the aiming point, reloading, reducing jams, oiling the 
mechanism, cooling the barrels, etc. 

This usable rate differs for different types of guns and mounts. 

The usable rate of fire of a belt-loaded, water-cooled gun on 
a mechanically controlled carriage may be as high as 500 or 
more shots per minute, while with a strip-loaded, air-cooled gun 
on a carriage without mechanical control the rate may not 
exceed 150 to 200 shots per minute. 

The rate of fire is dependent also upon the kind of fire used. 
The rate of fire of a single gun directed at a single point may 
be much greater than that which is interrupted after each 5 or 
10 shots to effect a change of aim. 

207. Rate of fire includes all pauses in the firing whether 
voluntary (as pauses to make a change of aiming points or to 
reload) or involuntary (as pauses because of malfunction or 
breakage of the mechanism). In this particular it differs from 
the cyclic rate in which such pauses are not included. 

208. Volume of fire is the total number of shots directed 
at a given target during any particular firing at that target. 

This term is sometimes used erroneously instead of " rate of 
fire " and " rate of impact." For example, a " volume " of 2,000 
shots may be directed at an objective by firing at the rate of 
2,000 shots per minute for one minute. The same " volume " is 
obtained by firing at the rate of 20 shots per minute for 100 
minutes (1 hour and 40 minutes). 

Hence 
Volume of fire==Rate of fire X Duration of fire. 

Rate of fire (average for single gunsW T° 1ume ° f fll ~ e -—— 

b & & ' Duration of fire X No. of guns firing 

Rate of fire (for an organization) = Volume of *l re 
Duration of fire 



203 MACHINE-GUN FIRING MANUAL. 






209. The rate of impact is the number of effective shots per 
minute per unit front of a given target. 

The definition of " effective shots " is taken from the Infantry 
Drill Regulations which states: 

" In combat shots which graze the enemy's trench or position 
and thus reduce the effectiveness of his fire have the approxi- 
mate value of hits ; such shots only, or actual hits, contribute 
toward fire superiority. " 

The " unit front " of a target is taken as 1 yard. 

In peace-time firing against silhouette targets no measure is 
afforded of the number of " shots which graze the enemy's trench 
or position " except the number of actual hits on the targets. 

As the center of impact approaches the center of the target, the 
number of hits increase. The number of " shots which graze " or 
what might be termed " near hits " also will increase. Thus, the 
number of actual hits serves as a very satisfactory measure of 
the number of eifective shots. 

Thus, the measure of the rate of impact is taken as the number 
of hits per yard per minute. For brevity the words " hits per 
yard per minute " often may be omitted. 

. For fire of a given rate and at given range and with no varia- 
tion in accuracy the rate of impact will vary inversely as the 
width of the target. If the target be of such depth as to require 
longitudinal as well as lateral distribution of fire to cover it 
effectively, it will vary inversely as the area of the target, the 
unit of depth being taken as the zone that is covered effectively 
by a single elevation. For example, in four minutes firing 800 
effective shots are placed on a target 100 yards wide. The rate 
of impact therefore is 2. Had the target been but 50 yards wide, 
then it could have been covered twice in four minutes and the 
rate of impact would have been 4. Had the target been 200 
yards wide and of such depth as to require two elevations, then 
the rate of impact would have been one-fourth of that on the 
original target, i. e., one-half. 



MACHINE-GUN FIRING MANUAL. 201 

210. Volume of impact is the average number of effective 
shots per unit front of target Obtained during any particular 
firing, i. e., it is the total number of effective shots divided by 
the number of units of front. 

As in the case of the rate of impact, the measure of the num- 
ber of effective shots is the number of actual hits. 

Assuming an equal distribution of fire, then upon volume of 
impact depends the number of casualties that are produced in 
the ranks of the enemy. Thus, with a volume of impact of 1 — 
an average of 1 hit per unit of front — then it is probable that 
about 63 per cent of the units of front will be struck. With 
volumes of impact of 2, 3, 4, 5, and 6, the probable percentage 
of units of front that will be struck are 86, 95, 98.7, 99.3, and 
99.8. 

It must be understood that this is based on the assumption 
that the distribution of fire continues throughout the entire 
target area. 

It appears, therefore, that when the volume of impact exceeds 
2 the additional casualties that may be produced are not com- 
mensurate with the additional expenditure of ammunition. The 
conclusion that the volume of fire should be no greater than is 
necessary to produce a volume of impact of 2 seems logical. 

This conclusion is correct only under the following conditions : 

(a) That the target is a body of men and is not merely a 
position or area. 

( b ) That the target is in the open, without defilade, and that 
its degree of vulnerability is constant and equal throughout its 
entire area. 

(c) That the casualties in the target are not replaced by 
reinforcements. 

When it is a question of rendering a certain area untenable, 
or of keeping a given body of the enemy confined to their de- 
filade, then it is rate of impact rather than volume of impact 
that is the predominant factor. In such a case volume of im- 
pact would be merely a result of the required rate of impact and 



202 MACHINE-GUN FIRING MANUAL. 

the length of time during which it must continue to accomplish 
a given tactical end. Thus, effective shots falling on each yard 
of the enemy's front at the rate of 1 per minute might not 
be sufficient even to disturb his aim, whereas were these shots 
increased to 60 per minute it might force him to retire to the 
cover of his trenches and not even attempt to return the fire. 
Of course such a fire would produce no casualties when the 
enemy had been forced to cover, but still it would be effective in 
that it gave fire superiority. 

211. Distribution Factor, — If continuous fire is maintained 
at a single aiming point, the rate of fire will be greater than if 
the fire is divided between two or more aiming points where it 
is necessary to cease firing while shifting and relaying the gun. 
The distribution factor is therefore defined as the ratio between 
the rate of fire and the cyclic rate. It is expressed as a decimal. 
For example, the cyclic rate for a certain gun is 500 ; the actual 
number of shots fired in a minute during distributed fire is 125. 
The distribution factor is therefore 125 -*- 500 = .25. It is evi- 
dent that a distribution factor of 1 is only possible when the gun 
fires at its cyclic rate, and that a value of the distribution factor 
of less than 1 is due to pauses in firing. The distribution factor 
should be kept as large as possible. This can be done in three 
ways: (a) Keeping the number of aiming points as low as con- 
sistent with the tactical misssion ; ( t> ) taking the least possible 
time for shifting fire from one aiming point to another ; and (c) 
reducing loading pauses and stoppages to a minimum. 

With skilled gunners it is possible to execute distribution 
either in width or depth (but not in both at the same time) 
while firing continuously and thus to maintain a distribution 
factor of 1. _ 

This method of fire increases the dispersion, and the ratio 
of this increase is greater for light type guns than for the heavy 
ones. 

Therefore, as the range increases, as the height of the target 
decreases, and as the skill of the gunner decreases, so will the 



MACHINE-GUN FIRING MANUAL. 203 

effectiveness of this class of fire decrease as compared with 
fire which is directed in bursts at several aiming points in 
succession. 

Hence, for targets of a given height there is a certain range 
beyond which it is more profitable to fire in bursts at successive 
aiming points, and below which a continuous fire will be the 
more profitable procedure. This dividing range is greater with 
skilled gunners and with mechanically controlled gun carriages, 
and it is less with unskilled gunners and with automatic rifles 
fired from the shoulder. 

Example: The cyclic rate of a certain gun is 600 shots per 
minute. The gunner is required to lay on 10 aiming points and 
fire 15 shots at each. He will have to shift his aim nine times 
and he requires four seconds for each shift. Loading is assumed 
to be done during pauses for relaying. The total time of firing 
the required 150 shots is, then, 15 seconds for the actual firing 
plus four times nine or 36 seconds for the shifting of aim, mak- 
ing 51 seconds in all. Now, at the cyclic rate 510 shots would be 
fired in 51 seconds. The distribution factor is then 150 -r- 510 = 
.294. 

If the gunner's skill is such that he requires but two seconds 
to shift his aim, the resultant distribution factor will be ob- 
tained as follows : 

15 seconds for firing + 18 seconds for shifting = 33 seconds. 
Fire at cyclic rate in 33 seconds = 330. 

150 
Distribution f actor — oon —-454. 

If the number of aiming points is reduced to 5, the amount per 
aiming point increased to 30, and the gunner's shifting time 
per aiming point remains as four seconds, gives : 

Fifteen seconds for firing + 16 seconds for shifting = 31 
seconds. 

Fire at cyclic rate in 31 seconds = 310 rounds. 

350 
Distribution f actor = ^r^r =.483. 



204 MACHINE-GUN FIRING MANUAL. 

212. Amount of fire is a term used to express the number of 
shots per burst that are or should be directed at each aiming 
point used in covering the width or area of a given target. 

The amount of fire, i. e., the number of shots to be directed 
upon any single aiming point, is dependent upon the range, 
the nature of the target, and the tactical situation. 

Should the situation be such that a certain amount of execu- 
tion was demanded throughout the entire front of the objective 
as quickly as possible, then the amount of fire would be rela- 
tively small, whereas were it such that the certainty of hits were 
a more important factor than the time element, then the amount 
of fire would be relatively great. Obviously, too, the greater 
the range and the smaller the target, the greater will be the 
amount of ammunition required to produce a given result. 

The figures in the body of the following table show, in rough 
approximation, the theoretical number of shots required per 
unit of front in order that there shall be a probability that 80 
per cent of those units of front will be struck. The table is 
tased on the assumption that the adjustment is precise and that 
the targets are in single dense lines. 

Should a greater or less effect be desired, then the number of 
shots should be increased or decreased accordingly. Twice 
the number of shots given in the table would make it probable 
that 95 per cent of the units of front would be struck, while 
one-half and one-fourth of the amounts in the table would re- 
duce the effect to 55 per cent and 33 per cent, respectively. 

Should it be necessary to distribute the fire in the direction of 
depth, then the amounts in the table should be increased by an 
equal amount for each two mils of searching ordered. With 
combined sights, the amounts given in the table should be used 
for each sight reading. 

While it is not to be expected that these figures will be memo- 
rized, nevertheless they should serve as a guide from which 
there should be no radical departure in practice. 



MACHINE-GUN FIRING MANUAL, 



205 



Kind of target. 



Range (yards). 



Head. 


Prone. 


Kneeling. 


Standing. 


15 


5 


5 


4 


25 


8 


6 


5 


35 


11 


7 


6 


45 


14 


8 


7 


55 


18 


10 


8 



Mounted. 



200.. 
400.. 
600.. 
800.. 
1,000 



218. Effectiveness of Fiee. — The true measure of the 
effectiveness of fire is the degree to which it keeps the enemy 
from directing an accurate fire upon our own troops. Thus, in 
its final analysis, the measure of the effectiveness of fire is a 
moral or psychological one. 

The immediate cause which produces this moral effect is the 
killing or disabling of the individuals in the enemy's firing line. 
it also may be produced by the enemy's apprehension of being 
killed or disabled, so thus a fire may be effective without pro- 
ducing any casualties in the enemy's ranks. In other words, 
his fear of being struck by a hostile bullet keeps the enemy down 
in his trenches without firing, or else prompts him to sacrifice 
accuracy of fire for the security of his shelter. 

For example, when a body of troops at A delivers such an 
effective fire on troops at B that they can not or do not return 
the fire, and thus the troops at A are enabled to advance on B 
without suffering casualties that would cause them to waver or 
halt, then the troops at A are said to have gained " fire 
superiority" over the troops at B. 

The measure of the effectiveness of fire, in peace-time firing, 
is that of the physical or material result produced on those 
targets by the fire in question. 

It is logical to assume that with troops of a given morale a 
great number of casualties will produce a greater moral effect 



206 MACHINE-GUN FIRING MANUAL. 

than a small number of casualties. It is also reasonable to as- 
sume that the effect on the mind is more intense when a given 
number of casualties are produced in a short space of time than 
it would b£ were that same number of casualties spread over a 
period of much longer duration. 

Therefore in peace-time firing the measure of the effective- 
ness of fire is taken as the number of casualties produced (fig- 
ures struck in the target) in a unit of time. 

Assuming an accurate and properly distributed fire, how do 
rates and volumes modify the effectiveness of fire? 

Consider first the animate target beyond the reach of defilade. 
In this case there are two factors to be considered in the meas- 
ure of effectiveness. They are the number of casualties pro- 
duced and the length of time that it takes to produce them. 

214. The number of casualties produced is dependent upon 
the volume of impact. Volume of impact is dependent upon the 
number of shots fired, and so, if the amount of fire is considered 
merely as a means of securing equal distribution, it may be 
said that volume of impact is dependent on volume of fire. 
Hence the number of casualties produced is dependent upon the 
volume of fire — the greater the volume the greater the number 
of casualties — and thus the greater the effectiveness. 

The length of time required to produce a given volume of fire, 
which is distributed throughout the target area in correct 
amounts at each aiming point, depends upon the speed with 
which the shots are delivered and the speed with which the 
direction of the fire is changed from aiming point to aiming point. 
Or, to use the terminology previously employed in this discus- 
sion, it depends upon the cyclic rate and the distribution factor. 
Thus the greater the cyclic rate and the distribution factor, the 
shorter the length of time required to produce a given volume 
of fire, and hence the greater the effectiveness. 

It may be said therefore that in general an increase in effec- 
tiveness of fire is produced by increasing the volume of fire, in- 
creasing the cyclic rate, and increasing the distribution factor. 



MACHINE-GUN FIRING MANUAL. 207 

215. The other case for consideration is that in which the 
object of the fire is not so much the production of casualties as 
it is to render certain positions or areas untenable — i. e., to make 
it certain that during a certain period of time there will be 
numerous casualties if the enemy attempt to occupy this posi- 
tion or to enter this area, 

As heretofore stated, the effectiveness of such a fire depends 
upon the rate of impact, assuming an accurate and properly dis- 
tributed fire. As rate of impact depends- upon cyclic rate and 
the distribution factor, it may be said that these two factors 
are the ones upon which depends the effectiveness of this class 
of fire. The volume of such a fire is a factor to be considered 
to the extent that it must be made certain that there is suffi- 
cient ammunition at hand to continue the fire at the required 
rate for the required length of time. 



CHAPTER III. 
ADJUSTMENT OF FIRE. 

216. Fire is said to be adjusted when the target lies within 
the effective portion of the beaten zone. Adjustment is more 
precise or less precise, depending upon whether the center of im- 
pact is in coincidence with, or in close proximity to, the center 
of the target or is somewhat removed from the center of the 
target. 

Adjustment is accomplished by one of the following means : 

1. By the use of a single correct elevation ; or 

2. By the use of a beaten zone artificially increased in depth ; 
or 

3. By the use of a single compromise elevation (battle sight) 
at short ranges, when the emergency is so pressing or the 
target so large that more precise adjustment becomes impos- 
sible or unnecessary. 

In deciding upon the method of adjustment to be used in 
any particular case, it is first essential to determine whether 
the battle sight or a more precise method is to be employed. 



208 MACHINE-GUN FIRING MANUAL. 

217. Choice of Means. — In deciding this question, it is to be 
remembered that the battle sight is an emergency sight to be 
"used on occasions when some material fire effect is demanded 
instantly, and when the delay incident to a more precise adjust- 
ment would render the fire valueless, notwithstanding the in- 
crease in material effect. The battle sight also is used when 
the objective is so large and at such close range that a more 
precise adjustment would have no material effect upon the 
accuracy of the fire. The third demand for the use of the battle 
sight is a psychological one, and would occur automatically 
with loss of fire control. 

THE BATTLE SIGHT. 

The battle sight is useful only within its zone and the height 
of the target directly affects this zone. By reference to plate 
64 it will be seen that when aim is taken at the bottom of a 
prone figure the fire is useful ; i. e., the target lies within the 
75 per cent portion of the cone only at ranges less than 510 
yards. Similarly, when aim is taken at the breast of the 
^kneeling figure, standing figure, and mounted figure the fire is 
useful only at ranges less than 600, 670, and 720 yards, respec- 
tively. 

This plate represents the battle-sight sheaf of the^ present 
automatic machine rifle, and corresponds to an elevation of 
-approximately 400 yards. 

It is seen, therefore, that adjustment by means of the battle 
sight consists not only in a decision ±o use it but also in the 
selection of an aiming point that will produce the greatest 
material results, and, in general, this aiming point would be 
at the lower edge of the figure when prone and at the breast 
when the height of the target exceeds that of the prone figure. 

218. The Use of a Single Elevation. — When it is decided 
that the battle sight is not to be used, the next question is 
whether one or more than one elevation is to be employed. 

The decision as to the number of elevations to be employed 
depends upon the range and the degree of precision with which 
ranges are determined. 



MACHINE-GUN FIRING MANUAL. 



209 



It is obvious that, as the 75 per cent zone marks the useful 
or effective position of the machine-gun sheaf, so one-half the 
depth of this zone marks the limit of error, in finding the range, 
which may not be exceeded with any expectancy or probability 
of effective material results. 

When ranging fire is impracticable, the usual methods of de- 
termining the range are single estimates by the eye, combined 
estimates by the eye, or measurement with a range finder. 

Experience has proven that single estimates by the eye will 
result in a probable error of about 15 per cent of the range, and 
that a combination of the estimates of a few men may reduce 
this error to 10 per cent. The probable error with the range 
finders of the self-contained base type is 2 per cent. 

For convenience of reference, the depths of the 75 per cent 
zone at various ranges and the amounts of the permissible and 
probable errors are tabulated as follows : 



Range (yards). 



Depth 


Permis- 


of 75 per 


sible 


cent zone. 


error. 


Yards. 


Yards. 


403 


201 


355 


177 


• 288 


144 


224 


112 


189 


94 


159 


79 


138 


69 


121 


60 


108 


54 


102 


52 


y6 


48 


90 


45 


84 


42 


77 


38 



15 per i 10 per 
cent cent 

error. error. 



2 per 
cent 
error. 



200... 
300... 
400... 
500... 
600... 
700... 
800... 
900... 
1,000. 
1,100. 
1,200. 
1,300. 
1,400. 
1,500. 



Yards. \ 
30 
45 ! 
60 ! 
75 
90 ! 
105 
120 I 
135 
150 
165 
180 I 
195 i 
210 ' 
225 | 



Yards. 

20 

30 

40 

50 

60 

70 

80 

90 

100 

110 

120 

130 

140 

150 



Yards . 



4 
6 
8 
10 
12 
14 
16 
18 
20 
22 
24 
26 
28 
30 



106101° 



-14 



210 



MACHINE-GUN FIRING MANUAL. 





II 

JZ 


«n = i> X 
a o i £ 

85s* 






H N°l. 
>IGHT (4 
UTOMAT 
RANGES 
T5 COME 


£ 


5£ 


SKETC 
3ATTLE J 
'OF THE A 
SHOWING 
US TARGE 






o 


o fe Q 




MACHINE-GUN FIRING MANUAL. 211 

A scrutiny of this table reveals the facts that — 

With single estimates by the eye (15 per cent error), the prob- 
able error exceeds the permissible error at distances beyond 600 
yards, and that therefore this range marks the maximum limit 
at which a single elevation can be employed with profit with 
ranges determined with this degree of precision ; 

With a few combined estimates by the eye (10 per cent error )> 
the limiting range for a single elevation is 750 yards ; and 

With the self-contained base range finder (2 per cent error ), 
it exceeds 1,500 yards. 

219. Raxgixg Fike. — When conditions are favorable, how- 
ever, these limiting ranges may all be increased by the use of 
ranging fire. 

The principle of ranging is simple. The sight is set at the 
range determined, the line of sight is directed upon the objective, 
a trial shot or string is fired, the impact of the projectiles is 
observed, an estimate is made of the correction to be applied to 
the rear sight in order to bring the center of impact to the cen- 
ter of the target, the reading of the rear sight is corrected ac- 
cording to the estimate, the line of sight is brought to bear again 
upon the objective and the gun is then ready to deliver fire for 
effect. 

It is obvious that the first requisite to successful ranging is 
that the target and the impact of the projectiles can be seen. 

This requirement demands : 

First. Daylight and a clear atmosphere. 

Second. That the objective and the terrain in its vicinity be 
visible to the firer or to the observer who assists him. 

Third. That the surface of reception be such as to give an 
indication of impact. 

The best indication of impact is given by water. On land the 
best indication is obtained when the projectiles strike in loose, 
dry, sandy soil which is devoid of vegetation. 

On ground that has been water-soaked by recent rains, or 
that is covered with a tall undergrowth such as grain, bushes, or 
rank grass the impact of the projectiles can rarely be seen. 



212 MACHINE-GUN FIRING MANUAL. 

220. There are also certain other factors to be taken into 
account, whereby a decision is reached as to whether ranging 
(even if the impact can be seen) will prove a profitable pro- 
cedure. 

These factors are : 

First. The zone in which the objective lies, i. e., whether it 
is within or without the zone of the battle sight. 

It is obvious that ranging is an unnecessary procedure and 
a waste of time against an objective which lies within the 
battle-sight zone, and against which it is necessary to use that 
sight, while beyond that zone it may or may not be required. 

Second. The degree of accuracy of adjustment of fire required. 

Thus, against a target of such area that, even with the maxi- 
mum probable error, the 75 per cent portion of the cone still 
covers the target, then a more precise adjustment of fire would 
make no material increase in the accuracy of the fire and there- 
lore ranging would not be necessary. 

Third. The nature of the objective and of the terrain in the 
immediate vicinity. 

Ranging is of no benefit against targets which, by their nature 
or that of the terrain, can evade fire for effect during the pause 
for observation of the ranging volley. Such targets are small 
columns which can effect a rapid and extended deployment, 
small parties of mounted men or any body of troops which is 
rapidly approaching defilade. 

The fire for effect will always give better results if preceded 
T>y ranging against targets which can not evade machine-gun 
fire. Lines of prone skirmishers and hostile machine guns or 
field pieces beyond the immediate reach of adequate cover are 
such targets. 

Ranging at moving targets is possible when the objective can 
not deviate materially from its course. Such targets are small 
boats attempting a landing, wagon trains, or artillery in column 
of route upon a road, or advancing or retiring skirmishers. 

Ranging fire while under hostile fire is of doubtful value. 



MACHINE-GUN FIRING MANUAL. 213 

Assuming that the impact and the target may be seen, the 
preceding discussion may be summarized thus : 

Ranging should be employed — 

When the probable error in the determination of the range 
exceeds half the depth of the effective cone of fire, i. e., beyond 
600 yards for single estimates, 750 yards for combined estimates, 
and then only against targets which can not evade the fire for 
effect. 

Ranging may be employed — 

Beyond the zone of the battle sight against moving targets 
which can not deviate materially from their course. 

Ranging should be proMbited — 

Against targets which, by a change of posture, position, or 
formation, can evade the fire for effect. This prohibition would 
not apply, for example, to such cases as ranging on a position, 
such as a trench, in contradistinction to ranging on the target, 
which might be the occupants of said trench. 

Ranging is superfluous — 

When the situation demands the use of the battle sight or 
when a more precise adjustment would make no material in- 
crease in the accuracy of the fire. 

Ranging is futile — 

When under hostile fire. 

It is readily seen that there are many preliminary conditions 
to successful ranging, all of which must be fulfilled before re- 
sorting to this procedure. 

The conclusion follows that ranging can not often be em- 
ployed ; this conclusion is confirmed by the experiences of 
machine-gun commanders in recent campaigns. 

However infrequent the opportunities for ranging, it should 
be the rule to employ it on every possible occasion when its use 
promises a more efficacious fire for effect. 

221. Elevation to Employ for Ranging. — It usually is best 
to employ what is believed to be the correct elevation or else 
to take what is known to be too low an elevation. In the former 



214 MACHINE-GUN FIRING MANUAL. 

case a few effective shots may result, and in either case observa- 
tion will be facilitated, as, other conditions being equal, it is 
easier to judge of impact that is short than of impact that is 
over. It is also true that there is a greater probability of ob- 
taining hits when the impact is a given distance short than when 
it is the same distance over. When the impact is short there 
is also the possibility of ricochets. 

222. The simultaneous employment of all the guns in rang- 
ing, using the same aiming point and the same elevation should 
facilitate observation. Such procedure will often result in 
giving indications of impact under conditions that otherwise 
might prove unfavorable. 

Ranging by platoon has the advantage of giving each platoon 
commander immediate access to the data necessary for opening 
an effective fire on that portion of the target assigned him. This 
implies, of course, a separate aiming point for each platoon. 
This method renders observation more difficult, but it may be 
employed to advantage when conditions indicate that observa- 
tion will be possible. At times it may be necessary, as, for ex- 
ample, when the objectives assigned the platoons are in different 
directions or at different ranges. 

Ranging by single guns is employed only under conditions that 
are most favorable for observation. Each gun is assigned its 
own aiming point. The necessity for this procedure might exist 
when the objective was widely scattered or when it occupied 
an irregular line or was on two or more lines at different ranges. 

The number of shots to be fired for ranging purposes. — The 
strings should be long enough to insure observation. On specially 
favorable soil 5 to 10 shots per gun may be found sufficient ; on 
ordinary ground 15 or 20 shots may be necessary, while on 
difficult ground or in a poor light 30 shots per gun may give but 
scant indications. 

At first glance this amount might seem an excessive ex- 
penditure . for ranging purposes. If a fewer number of car- 
tridges will insure observation, so much the better ; but if not, 



MACHINE-GUN FIRING MANUAL. 215 

then the full number that are required should be' expended 
without hesitation, as ranging is for the purpose of securing 
an accurate fire for effect. With proper observation the fire 
for effect may be presumed to give its maximum results, while 
without it the enemy may find these results merely an annoy- 
ance. Fire should seek not to annoy but to annihilate the 
enemy. 

When the impact is not observed after the first ranging 
string, it becomes a question whether ranging is to be con- 
tinued or fire for effect opened without further prelude, some 
other means of adjustment being sought. 

This depends upon the time available before either the target 
disappears altogether or an overwhelming hostile fire is brought 
to bear upon the guns, the location of which often will be be- 
trayed by the first ranging burst. 

It will depend, too, upon whether it is considered better to 
disturb the enemy's aim with fire of some effect or to trust to 
the possibility of securing later the maximum effect after exe- 
cuting additional ranging in the face of an undisturbed hostile 
fire. 

223. The element of suddermess or surprise is one of the 
essential characteristics of the successful application of ma- 
chine-gun fire. — Continued ranging not only robs the gun of this 
essential characteristic, but ranging while under a storm of hos- 
tile musketry or artillery fire usually is worse than useless, if 
it can be done at all. Hence the conclusion that the least possi- 
ble time should elapse between ranging and fire for effect and 
when in contact with the enemy the employment of more than 
one string of shots for ranging purposes is the exception. Hoiv- 
ever, the first ranging strings must be long enough to insure 
observation, for otherwise it is better to dispense with ranging 
altogether and seek some other means of adjustment. 

224. The choice of a point in or near the objective on which 
to execute the ranging should be made with an eye to facility 
of observation as the most important consideration. With the 



216 MACHINE-GUN FIRING MANUAL. 

aid of the field glass the terrain in the vicinity of the target 
is subjected to a rigid scrutiny, the selection falling on that 
portion which promises the clearest indications of impact. 

. It is not essential that the ranging fire be directed at the 
target itself. Favorable soil in the vicinity will answer as 
well, provided the proper allowances are made when the sight 
reading is corrected. 

When all portions of the terrain appear equally favorable 
for observation, ranging should be directed at some portion of 
the target itself in order that advantage may be taken of the 
possibility of chance effect. Under such circumstances the 
center of the target should be chosen rather than either flank, 
as the full effect of the lateral dispersion is thus secured. 

The correction of sights as a result of ranging is based upon 
the observation of the impact and . the subsequent estimate as 
to its distance and direction from the objective. 

In known-distance practice the strike of the bullet is on a 
vertical surface, and when the position is shown by the mark- 
ing disk the sight is corrected accordingly. 

In combat, however, the observation of impact may be on a 
surface that is rising with respect to the line of sight. In 
such cases the correction of the sight must compensate not 
only for the horizontal distance, short or over, but also for 
the vertical distance above or below the objective. 

Referring to plate 65, suppose W to represent a vertical sur- 
face and the point T to be the target. If a shot fired at T 
strikes at the point H the sight correction to be applied cor- 
responds to the vertical distance HT. If T be assumed to be a 
horizontal surface AT, the same trajectory will cut the hori- 
zontal surface at H" and the sight correction to be made will 
correspond to the horizontal distance H"T. If T be assumed 
to be on the surface STS, rising with respect to the line of 
sight, the same trajectory will intersect this sloping surface at 
the point H'. The required correction in this case embodies 
two elements, a correction for the horizontal distance short, 



MACHINE-GUN FIRING MANUAL. 



217 



H'V, and a correction for the vertical distance below the tar- 
get, represented by H'T'. 

Similarly the correction to be applied to a shot that is over is 
represented by the distance H" ' T" plus H" ' V". 

It is therefore apparent that when the target is on sloping 
ground the corrections applied to the rear sight will be too 
small unless in addition to the correction for the actual distance 
short or over allowance is made also for the angular distance 
of the point of impact above or below the target. 




Plate 62. 



In practice the actual distance in yards that the center of 
impact is distant from the target must, in most cases, be esti- 
mated. The vertical correction, however, may be measured with 
a fair degree of accuracy by using the type EE field glass with 
the range and mil scale. 

To measure the amount of this vertical correction with the 
field glass, place the graduation of the range scale correspond- 



218 MACHINE-GUN FIRING MANUAL. 

ing to the elevation actually used in coincidence with the target. 
Then the graduation opposite the point where the impact was 
noted will be the elevation necessary to take in order to correct 
for the vertical error. It is to be noted that this vertical correc- 
tion gives the range (in terms of the sight) to the point of 
impact. 

The vertical correction having been made, then the correction 
is completed by adding (if the impact is short) or subtracting 
(if the impact is over) a number of yards equal to the estimate 
of the horizontal distance from the impact to the objective and 
setting the sight accordingly. 

Plate 63 illustrates this method. 

Assume the range to have been estimated at 800 yards. Then 
with the 800-yard graduation held opposite the target the splash 
of impact is observed opposite the 1,100-yard graduation and is 
estimated to be 150 yards short. The full correction therefore 
would be 1,100 yards (vertical correction) plus 150 yards 
(horizontal correction) or a final elevation of 1,250 yards as a 
result of this observation. 

Lacking a field glass fitted with a sight scale, this vertical 
correction can be determined quite as accurately if the observer 
is provided with a mil scale and a table of elevations in mils. 
( See range table, par. 120. ) 

Taking the same example, the observer uses his mil scale to 
measure the vertical angle between the target and the impact 
and finds it to be about 11 mils. He now refers to his range 
table and finds the elevation for 800 yards to be 9.4 mils and 
to this he adds the vertical correction of 7^, making a total of 
16.9 mils. Referring to the table again, he finds that an eleva- 
tion of 16.9 mils corresponds to a range of about 1,100 yards. 
To this 1,100 he adds the estimated shortage of 150 yards and 
thus obtains the same final correction as before, 1,250 yards. 

225. Combined Sights and Searching Fire. — When the 
means are lacking with which to determine the range with the 
requisite degree of accuracy and it is impracticable to employ 



MACHINE-GUN FIRING MANUAL. 



21fr 



Vertical Correction . 
Full Correction 




TARGET 



10 

o""'% IMPACT 



- 15 



L 20 

Plate 63. 



220 



MACHINE-GUN FIRING MANUAL. 



ranging fire it then becomes necessary artificially to increase 
the depth of the beaten zone. This is done by using combined 
sights or searching fire. 

When combined sights are used the angular difference between 
sight readings is for all practical purposes constant for all 
ranges below 1,500 yards and is equal to about 2. mils. This is 
equal approximately to the angular difference in elevation be- 
tween 800 and 900 yards. 

226. The information required in regard to the. number of 
elevations to be used or the depth of searching (in mils) that 
is required, with various assumed probable errors, may be had 
in rough approximation by reference to the following table. 
The amounts in the body of this table indicate the limiting 
ranges, in yards, up to which the number of elevations or mils 
indicated will create the required depth of beaten zone. 



Number 
of ele- 
vations 
required. 


Number 
of mils 
search- 
ing re- 
quired. 


Probable errors. 


15 per 
cent. 


10 per 
cent. 


5 per 
cent. 


1 
2 
3 
4 



2 
4 
6 


600 
1,000 
1,200 
1,400* 


750 
1,300 
1,500 















227. The employment of more than three elevations is of 
-questionable utility involving a large expenditure of ammuni- 
tion with doubtful effect. No hard-and-fast rule will cover all 
possible conditions. The machine-gun commander must base 
his decision upon the conditions of the combat at the time. 

228. Ammunition being abundant, its replenishment as- 
sured, and a broad and deep target giving promise of a high 
percentage of hits, the employment of more than three eieva- 



MACHINE-GUN FIRING MANUAL. 821 

tions may be justifiable. On the other hand, ammunition being 
scarce, its renewal improbable, and the target lacking in density 
as well as depth, the employment of even two elevations is a 
doubtful expedient. Between these two extremes, conditions 
alone determine the use of any particular number of elevations ' 
in combination. 

229. The combination of elevations should insure the cen- 
ter of the resulting beaten zone corresponding to the estimated 
range. Thus, using two elevations at a range determined as 
1,000 yards, one sight would be 1 mil below 1,000 and the other 
1 mil above. With three elevations, one sight would be at 1,000, 
one 2 mils below, and the third 2 mils above. 

When from any cause the number of guns available is less 
than the number of elevations required, the effect of combined 
sights may be produced by searching fire. 

230. Fike For Effect. — A machine gun can not fire con- 
tinuously throughout an action, but is employed when for short 
intervals it is sought to concentrate a great volume of fire on a 
relatively small portion of the enemy's front. The effectiveness 
of this fire, other conditions being equal, is in proportion to its 
suddenness, and surprise effect. 

To obtain the maximum effect, all orders and instructions 
relative to the conduct of fire should be given before the fire 
for effect is opened. If ranging is to be employed, these orders 
and instructions should be given before the first ranging shot is 
fired in order that further orders may be confined to announcing 
the correct elevation and giving the command to fire. 

As ranging is executed simultaneously by all the guns under 
the immediate control of the machine-gun commander, so should 
the burst of fire for effect be by his order and from all the guns 
at once. This method will be productive of a greater moral 
effect. 

It has been enunciated as a principle that the shallow-beaten 
zone of the machine gun demands a wide and deep target to 
secure the maximum material results. But with equal truth 
it may be said of any weapon of precision that the larger the 



222 MACHINE-GUN FIRING MANUAL. 

target the more hits are to be expected ; hence this principle 
should not be misconstrued in such a manner that in its prac- 
tical application the fire of machine guns is withheld unless a 
broad, deep target presents itself within effective range. 

It may happen that machine guns operating with the advance 
cavalry have occasional opportunities to fire on broad, deep 
targets, and that more rarely such opportunities would come to 
machine guns operating in the minor combats preceding a gen- 
eral engagement in pursuit or retreat or in minor warfare. In 
an infantry engagement of any magnitude, however, in which a 
decision is sought, such opportunities will be very rare if not 
entirely lacking, except during the assault. 

The usual targets presented in the infantry combat prior to 
the assault are the heads and shoulders of the hostile infantry 
in trenches, prone skirmishers, small groups of men engaged in 
the service of machine guns or field pieces, and groups or indi- 
viduals advancing or retiring by running or crawling. 

The infantry will be obliged to wrest a superiority of fire 
from troops presenting such targets. Hence the infantry ma- 
chine gun must lend its aid, not because they promise a great 
number of hits, but because the advance of the infantry will be 
checked unless the hostile fire is neutralized. 

The machine guns do not open fire every time the skirmishers 
pause in their advance. The machine-gun commander's mission 
usually will require him to place his guns in such position that 
he can deliver an effective fire on the enemy during the assault. 
Prior to that time his fire is limited to occasions when the 
infantry is unable to hold its own in the fire fight, or, when not 
required for this purpose, he may fire on specially favorable 
objectives promising a large percentage of hits. 

231. There should be no hesitancy in directing the fire of 
machine guns against any hostile force, irrespective of their 
numbers, the weapon they employ, their formation, and whether 
or not the probability of material results is great or small, when 
it is permitted by the mission and demanded by the tactical 
situation. 



MACHINE-GUN FIRING MANUAL. . 223 

EFFECT TO BE EXPECTED AGAINST VARIOUS TARGETS. 

Prone skirmish lines. — Their ordinary density is about oik* 
man per yard of front. Such a target, though lacking in depth, 
offers the machine gun a fair remuneration in hits at ranges of 
about 600 yards or less. At ranges greater than 600 yards the 
employment of an accurate range finder or of ranging fire is 
necessary in order to secure material results that are in the 
least degree commensurate with the expenditure of the ammu- 
nition. 

The percentage of hits decreases with the density of the skir- 
mish line. 

232, Theoretically, the fire of machine guns, beyond close 
ranges should not be employed against a shallow line whose ele- 
ments are separated by an interval greater than the natural 
lateral dispersion of the cone. At 500 yards this interval is 
about 3 yards. 

Practically, however, the necessity for firing on a thin line 
seldom exists, as riflemen rarely require aid in obtaining a 
superiority of fire in such cases. 

It may be assumed that the skirmish lines attacked by ma- 
chine guns will be ordinarily of a density of about one-half to 
one man per yard. Distributed fire must be used against such 
lines. At the longer ranges and against irregular lines any at- 
tempt to "sweep " the target — i. e., to change the line of sight 
while firing — will result in creating merely a dangerous area 
somewhere in the vicinity of the objective, the actual number of 
hits being comparatively small. At close ranges, however, and 
against dense targets, sweeping fire is effective. 

Either continuous or intermittent fire is employed against this 
class of target. 

At distances greater than 600 ~y ai *ds, when it is impracticable 
to employ either ranging or accurate range finders, recourse to 
the use of combined sights or searching fire against this class 
of target is of doubtful value on account of the great expendi- 



224 MACHINE-GUN FIRING MANUAL. 

ture of ammunition necessary to attain the desired results un- 
less the fire be delivered from a flank. 

Experience has proven that an increase in material effect may 
be expected when machine guns engage a linear target from a 
flank and also when the line of fire is oblique to the front of the 
target. . 

Unless the supply of ammunition is abundant and can be re- 
newed promptly, it is better to withhold the fire of the machine 
guns until a critical stage of the engagement. 

233. Infantry in trendies is attacked in the same manner 
as prone skirmish lines. 

In the attack of hostile machine guns, fixed fire at each gun is 
clearly indicated. By distributing the fire against as many 
guns as possible at the same time, fewer guns are left undis- 
turbed to continue their fire with almost peace-time accuracy. 

When engaging a superior number of hostile pieces, the first 
gun to silence its opponent should be turned at once on one of 
the guns that has remained unmolested. Under these circum- 
stances it is best to concentrate on the center guns first, and, 
when these have been silenced, to attack both flanks. 

The enemy's guns should be engaged piece for piece by the 
flank guns when they are inferior in number. The center guns 
lend their aid where it appears to be needed most, usually 
against guns where the effect of fire is difficult to observe, or 
against those whose fire seems undiminished. 

234. Artillery. — A frontal attack against shielded guns in 
position can be of little avail and is to be avoided. Opportuni- 
ties to attack artillery in position from the flank or rear should 
be seized, employing the same methods of fire as are used in the 
attack of machine guns. 

235. Advancing of Retiring Skirmish Lines. — On account 
of their lack of depth, and also the wide intervals that are usual 
at the longer ranges, such targets will not ordinarily prove 
favorable objectives at ranges exceeding 1,000 yards. As the 
shorter ranges are reached, skirmishers in motion are at best a 
difficult objective. 



MACHINE-GUN FIRING MANUAL. 225 

They can evade the fire by lying down, and their movements 
being at short irregular intervals, expose them to the fire of 
the guns for very brief periods. The movement of the skirmish- 
ers usually will be from cover to cover. Advantage is taken of 
this procedure to determine the correct elevation while the 
skirmishers are halted, so that when they emerge from cover 
fire for effect can be opened without delay. 

Distributed or sweeping fire is used. 

If the distance to the nearest cover is very great, it will be 
necessary to make allowances for the constant change in range 
by setting the sight a trifle above or below the true elevation. 

236. Columns. Itecourse is usually had to combined sights' 
or searching fire in order to secure distribution against columns. 

237. Targets Moving Aceoss the Line of Sight. — Distribu- 
tion against targets of this character may be obtained by hold- 
ing on a single point with fixed fire. Fire is opened as the 
leading element passes the aiming point and is continued as long 
as any portion of the target remains in the cone of fire. The 
point of aim is moved ahead of the target as often as necessary. 

238. Fire Against Aircraft. — Experience has shown that 
machine-gun fire is ineffective against aircraft unless the guns 
are employed in large masses. Consideration also should be 
given to the fact that aircraft usually fly far beyond the effective 
range of small arms and at very high speeds. 

106191°— 17 15 



PART V- 



TARGETS AND RANGES. 

239. Targets are divided into three classes : 

( a ) Target for obtaining the sight setting of machine guns. 

(b) Known-distance targets (for machine guns). 

(c) Field targets (for rifle and machine guns). 

240. Target for Obtaining Sight Setting of Machine 
Guns. — This target, known as target B, is a square 6 feet on a 
side, black circular bull's-eye 20 inches in diameter ; center ring, 
37 inches in diameter ; inner ring, 53 inches in diameter ; outer 
remainder of target. This target is used for the determination 
of sight settings for machine guns. 

241. Known-Distance Targets. — There is but one target 
used for this practice. It is of paper mounted on a rectangular 
frame 3 feet by 20 feet. 

This paper is ruled with horizontal lines 1 inch apart and with 
vertical lines 3 inches apart. 

The aiming points on this target are made with black pasters 
arranged to represent such formations of troops as may be de- 
sired by the instructor. 

For reference, however, four arrangements of aiming points 
are given as types. These are shown in plates 67 and 68 and are 
known as targets MGA, MGB, MGC, and MGD. 

242. Target MGA, figure 1, plate 67, is used for practice in 
holding and in fixed fire. 

The aiming points are single black pasters arranged in 10 
vertical lines of three aiming points per line. These vertical 
226 



MACHINE-GUN FIRING MANUAL. 227 

MACHINE GUN TARGETS 
Sketch No. 15. 
MGA 



Fig. 1. 

MGB 




Fig. 3. 
Plate 64. 



228 MACHINE-GUN FIRING MANUAL. 

lines of aiming points are placed in the center of each 2 feet 
of width of the target, and in each line the upper paster is 9 inches 
from the top of the target, the lower paster 3 inches from the 
bottom of the target, and the middle paster 21 inches from the 
top and 14 inches from the bottom of the target. 

243. Target MGB, figure 2, plate 67, is used for distributed 
fire, searching fire, and a combination of these two methods. The 
aiming points consist of two black pasters side by side, and they 
are arranged in two horizontal lines extending across the entire 
width of the target. One line of aiming points is placed 3 inches 
and the other 22 inches from the bottom of the target. The 
aiming points are placed between two horizontal lines and in 
the center of the intercept between each two vertical lines. 

244. Target MGC, figure 3, plate 67, is used for practice 
against such a target as would be presented by a column of 
troops marching on a hillside. The aiming point is a black 
strip 4 inches wide and 3 feet long placed parallel to the diag- 
onal of each 5-foot width of the target. The four strips alternate 
on the ascending and descending diagonals ; the center of each 
strip is on a diagonal line bisecting the 5-foot space allotted 
to it, and the lowest corner of the strip is 3 inches above the 
bottom of the target. 

245. Target MGD, plate 68, is used for instruction and 
record practice. The aiming points are made of black pasters 
designed to represent some of the tactical objectives at which 
machine-gun fire might properly be directed. 

The "scoring spaces" coincide with the aiming points in 
two of the cases. In the other two cases the scoring spaces are 
placed on the target at the proper ordinate above the aiming 
point, so that the score may. be determined at once. 

The target is divided vertically into four equal sections, in 
the centers of which the designated aiming points are placed as 
described in paragraph 246. 



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230 MACHINE-GUN FIRING MANUAL. 

GROUP 1. 

240. Objective: A 15-yard section of skirmish line on a hill- 
side at a range of 300 yards. 

Aiming point: A black strip 50 inches long and 5 inches high 
placed on the target with the lower enemy right corner on the 
5-inch line, extending diagonally upward to the enemy left, and 
crossing 15 of the vertical sections of the target. The ends of 
the strip coincide with the two' vertical lines on the target, in- 
cluding the 15 vertical sections, the resulting form of the aim- 
ing point being a parallelogram (a rhomboid). 

Scoring spaces: The range being point blank, the scoring 
area and aiming point coincide, and the score is determined from 
the hits in the black aiming point. The vertical lines on the 
target are continued through the black aiming point, dividing 
the latter into 15 rhomboids, each of which constitutes a scor- 
ing space. 

Possible score, 15 points. 

GROUP 2. 

Objective: Two squad columns at a range of 300 yards, at an 
interval of 8 yards. 

Aiming points: Two black rectangles each 10 inches long and 
3 inches wide, placed with the lower edge on the 15-inch line 
of the target, and with eight vertical sections of the target (24 
inches) interval. 

Scoring spaces: The range being point blank, the scoring areas 
and aiming points coincide. Each aiming point is divided into 
10 rectangular scoring spaces, each 1 inch high and 3 inches 
wide, by continuing the horizontal lines of the target across 
the black surface. 

Possible score, 20 points. 



MACHINE-GUN FIRING MANUAL. 231 

GKOUP 3. 

Objective: A 25-yard section of trench at 1,000 yards. 

Aiming point: A black strip 25 inches long and 1 inch high 
placed between the 5-inch and 6-inch lines and extending across 
8i vertical sections of the target. 

Scoring spaces: A rectangle with dimensions identical to those 
of the aiming point is outlined exactly above it and between the 
15 and 16 inch lines. This rectangular scoring area is divided 
vertically into 25 scoring spaces, each 1 inch square. 

Possible score, 25 points. 



Objective: A 15-yard section of skirmish line on a hillside at 
a range of 600 yards. 

Aiming point: A black strip 25 inches long and 3 inches high 
placed on the target with the lower enemy left corner on the 
5-inch line and extending diagonally upward to the enemy right 
across 7| vertical sections of the target. The ends of the strip 
are vertical, the resulting form of the aiming point being a 
rhomboid. 

Scoring spaces: A rhomboid with dimensions identical to those 
of the aiming point is outlined exactly above it, the upper edge 
of the aiming point forming the lower edge of the scoring space. 
This scoring area is then divided into 15 equal scoring spaces by 
bisecting vertically each rhomboidal section made by the vertical 
lines of the target. 

Possible score, 15 points. 

Total possible score, 75 points. 

FIELD TARGETS. 

247. Target E. — A drab silhouette about the height of a 
soldier in the kneeling position, made of bookbinders' board or 



232 MACHINE-GUN FIRING MANUAL. 

other similar material. Hits on all field targets count 1, and 
any shot cutting the edge of a silhouette is a hit. 

248. Target F. — A drab silhouette about the height of a 
soldier in the prone position, made of bookbinders' board or 
other similar material. The life of targets E and F can be 
materially prolonged by pasting on fresh paper silhouettes when 
the figure becomes too much damaged by shots. These targets 
are used as stationary targets as well as on the moving and 
disappearing appliances. When necessary these targets are 
fastened to wooden staves with tacks and tin washers. 

249. Target G. — Falling target. The target is made of soft- 
wood about the shape, size, and color of the prone silhouette F. 
These targets should be placed in small pits (1 by 2 feet) so 
that about 9 or 10 inches of vertical protection is given the base 
and mechanism ; only the face of the target should show to the 
front. If the wooden figure becomes unserviceable, it may be - 
repaired at the post. 

250. Target H. — Targets E or F inserted in a slit at the 
end of a marking disk staff- or pole and fastened with wooden 
pegs. The staffs are held in the hands of markers or in brack- 
ets on the inside of the crest of the pit. The targets are held 
faced to the front. When struck they are turned rapidly so as 
to show the white side, and then back to the original position. 

251. Target I. — Beam disappearing target. The visible tar- 
get represents a line of prone or kneeling figures at suitable inter- 
vals. In close order eight figures are mounted on each beam. 
The figures are targets E and F, mounted on the regulation 
staves, which are modified by having the points cut off, so that 
but 6 inches project below the bottom of the figures. 

The beam itself is made up of one piece of 2 by 6 inches by 
20 feet long, one piece 1 by 6 inches by- 20 feet long, and 1 by 6 
by 20 inch sections fitted between them, as shown in plate. 

The beam is laid in a shallow trench, targets horizontal, and 
a stake is driven in front of the beam at each end. The ropes 
from the operating standard lead to the pit (direct and via the 



MACHINE-GUN FIRING MANUAL. 233 

rear ring stake) and the beam is turned through 90°, exposing, 
and lowering the targets by pulling on the appropriate ropes. 
The rope system is in duplicate, so that if one rope is cut by a 
bullet the target can still be worked. Two or more beams can 
be coupled together and the whole operated from the center. 
There should be two end stakes for each beam. The operating 
standard should be painted a neutral color, have earth rubbed 
on it, or have bundles of vegetation tied to it. The ropes should 
also be of a neutral color. 

This apparatus requires but one man for its operation, even 
if two beams are coupled together. The pit should be deep 
enough to give protection, and the earth therefrom should be 
spread out into a low embankment and concealed by grass or 
brush. 

252, Target K. — Sled target. The disappearing target 
beam (target I), is lashed lengthwise to two sleds. A rope 
from 200 to 300 yards long is used to pull this target and an 
escort wagon and team has been found to be the best motive 
power. The rope can be run through a snatch block, and the 
team concealed by inequalities of the ground. If no cover can 
be found for hiding the sled before it starts, it can be easily 
masked with brush, grass, etc., which will fall when the targets 
start. 

RANGES. 

GENERAL CONSIDERATION. 

253. Classes. — There are two general classes of ranges: 
Class A ranges, which are more or less limited in extent and 
which are equipped for known-distance rifle practice. This 
range can also be used for machine gun known-distance firing 
and is used for the purpose of determining the sight setting of 
the guns. Class B ranges, which are of extended area and 
diversified terrain, and which are used for combat firing. As 
machine-gun organizations will often be limited to class A 



234 



MACHINE-GUN FIRING MANUAL. 



*'-- 




TARGET B. 








Plate 66. 



MACHINE-GUN FIRING MANUAL. 235 

ranges and will usually take part in field firing with other 
troops on class B ranges, it is essential that all machine-gun 
officers be thoroughly familiar with the different class of ranges. 

254. Rules for Selection. — As the nature and extent of 
the ground available for target practice and also the general 
climatic conditions are often widely dissimilar for different 
military posts, it will not be possible to prescribe any particu- 
lar rules governing the selection of ranges but only to express 
certain general conditions to which ranges should be made to 
conform as far as may be practicable. In view of the extreme 
range and penetration of the bullet used in the service, it will 
be found necessary in the case of many posts to have machine- 
gun practice conducted at a distance of several miles from the 
post, necessitating the establishment of a camp on or near the 
range. The machine-gun practice can then be conducted unin- 
terrupted by the routine of post duties. 

255. Security Necessary. — For posts situated in thickly 
settled localities, where the extent of the military reservation 
is limited, the first condition to be fulfilled is that of security 
for those living or laboring near or passing by the range. This 
requirement can be secured for a class A range by selecting 
ground where a natural butt is available or by making an 
artificial butt sufficiently extensive to stop wild shots. 

The following diagram shows the shape and dimensions of 
the area within which life or property might be endangered by 
rifle or machine-gun fire in a given direction, and outside the 
boundaries of which there exists a reasonable degree of safety. 

In determining the shape and dimensions of this area cer- 
tain basic assumptions are made. Actual conditions must con- 
form to these basic assumptions if there is to be a reasonable 
assurance of safety outside the boundaries of this area. 



236 



MACHINE-GUN FIRING MANUAL. 



4U*lM*4 




"•'fit. 






TARGET K 
Plate XXIII 

Plate 67. 



MACHINE-GUN FIRING MANUAL. 237 

These basic assumptions are as follows : 

1. That the firing point is on the line CD and that the firing 
line is deployed facing toward B and on a front of not to ex- 
ceed 200 yards. If the front of the firing line does exceed 200 
yards, then the w T idth of the zone CDEF must be increased ac- 
cordingly. 

2. That the target lies within the boundaries of the zone 
CDEF, the width of this zone being increased if the target pre- 
sents a front of over 200 yards. 

3. That the direction of the fire in azimuth will not deviate, 
either through accident or design, by more than 6° from the 
median line AB. Should there exist the probability of a devia- 
tion greater than 6°, then the angles GCE and FDH, by which 
the boundary lines GJ and HK are located, must be increased 
accordingly. 

4. That, on ordinary soil, the direction taken by bullets w T hich 
happen to ricochet will not deviate more than 30° from the 
median line AB. 

When the surface of the ground within the area CDKJ pre- 
sents such features as woods, exposed rocky formations, steel 
or iron structures, or any other natural or artificial features 
that might cause ricochets to be deflected at angles greater 
than 30°, then the angles MCE and NDF, by which the bound- 
aries MC and ND are located, must be increased accordingly. 

When such an increase in these angles becomes necessary, 
the sides MC and ND do not change in length but remain each 
1,400 yards. The sides IM and LN remain parallel to the 
median line AB, but are farther apart and longer. For all 
practical purposes absolute safety from ricochets is attained 
wiien, under most unfavorable conditions, these angles are in- 
creased from 30° to 85°. 

It will be noted that these four conditions modify only the 
width of the danger zone. 

These widths may also be reduced by proper defilade on a 
protected range. 



238 



MACHINE-GUN FIRING MANUAL. 
B 




Boundaries indicated by unbroken lines. 



MACHINE-GUN FIRING MANUAL. 239 

The distance from the firing line, CD, to the line IJKL is 
2,700 yards and marks the extreme range of the final impact 
of ricochets. There would be no conditions that would necessi- 
tate an increase in this distance, though proper defilade and 
proper surfacing of the ground on a protected range might per- 
mit it to be shortened. 

For practical use in connection with firing on class B ranges 
a diagram like the one shown above is drawn on tracing linen 
or other similar material and a scale of yards added on the 
median line AB, the zero of this scale at the firing line CD. 
The scale of this drawing would be the same as the scale of 
the map of the class B range. 

By applying this drawing to the map it can be told at a. 
glance whether -or not it is safe to fire from a given point and 
in a given direction. A safe site for a given firing exercise hav- 
ing been determined upon, it also will serve to show what 
measures must be taken to keep this area free of traffic while 
the firing is in progress. 

256. Direction of the Range. — If possible, a range should 
be so located that the firing is toward or slightly to east of 
north. This gives a good light on the face of the targets during 
the greater part of the day. However, security and suitable 
ground are more important than direction. 

257. Best Ground for Class A Range. — Smooth, level 
ground, or ground with only a very moderate slope, is best 
adapted for a range. If possible the targets should be on the 
same level with the firer or only slightly above him. Firing 
downhill should, if practicable, be avoided. 

258. Size of Range. — The size of the range is determined 
by its plan and by the number of troops that will fire over it 
at a time. There are two general plans used in range con- 
struction — one with a single target pit and firing points for 
each range, the other with its firing points on one continuous 
line, the target pits for the various ranges being in echelon. 
The latter type requires more ground but admits of firing at 
different ranges at the same time. 



240 MACHINE-GUN FIRING MANUAL. 

259. Artificial Butts. — If an artificial butt is constructed 
as a bullet stop, it should be of earth not less than 30 feet high 
and with a slope of not less than 45°. It should be extended 
about 5 yards beyond the outside targets and should be placed 
as close behind the targets as possible. The slopes should be 
sodded. 

260. Hills as Butts. — A natural hill to form an effective 
"butt should have a slope of not less than 45° ; if originally more 
gradual it should be cut into steps, the face of each step having 
that slope. As a temporary expedient the face of the hill may 
be plowed perpendicularly to the range, but as the bullets soon 
cut down the furrows this measure must be frequently repeated 
to prevent the danger of ricochets. 

261. Numbering of Targets.— Each target should be desig- 
nated by a number. The numbers for ranges up to 600 yards 
should be at least 6 feet in height and should be painted black 
on a white background. The Arabic is preferable to the Roman 
notation, being more readily comprehended by the soldiers ; if 
made of the size suggested, they will always be quickly recog- 
nized. They should be placed on the butt behind each target, 
out not so far above as to prevent the soldier seeing the number 
when aiming at the target. 

262. Firing Mounds. — If it becomes necessary to raise a 
firing point on account of low ground, a low mound of earth no 
higher than absolutely required should be made. The mound 
should be not less than 8 feet square, level, and sodded. If the 
entire firing line is raised, the firing mound must be not less than 
8 feet wide on top, level, and sodded if possible. 

263. Pit Shed. — A small house or shed should be built in 
or near the target pit, in which the marking disks and signal 
flags and spare parts of the target frames for making immediate 
repairs should be stored. It should be sufficiently large to afford 
a shelter for the markers in case of a sudden storm. 

264. Danger Signals. — One or more danger signals will be 
displayed near the range to warn passers-by when firing is in 



MACHINE-GUN FIRING MANUAL. 241 

progress. These signals will not be placed in such a position as 
to serve as streamers for judging wind on the range. They 
should be placed on the roads or on the crest of the hill where 
they can be plainly seen by those passing. 

265. Range House. — On large ranges where competitive 
firing is held a house containing a storeroom and several office 
rooms should be erected in some central place, off the range, but 
in its immediate vicinity. Such facilities as will enable visitors 
to satisfactorily witness the firing should also be provided. 

266. Scobees' Tables. — The range should be provided with 
scorers' tables and benches. 

MACHINE-GUN EANGES. 

267. Aeea. — For each target used, the machine gun known 
distance range should be a level open space about 40 yards in 
length (in the direction of the line of fire) and 10 yards in width. 

268. Selection of Site. — With obvious modifications, the 
rules for the selection and preparation of class A ranges apply 
with equal force to the machine-gun range. 

269. Plan of Range. — The target frame is carried on a 
truck, which runs on a light track leading from the firing point 
to the position of the target, 27J yards distant. 

At this distance (1,000 inches) 1 mil subtends an angle at the 
target of 1 inch. At a range of 1,000 yards 1 mil subtends an 
angle of 1 yard ; therefore all calculations, firing data, etc., on 
the machine-gun range of 27|- yards are correct to scale. 

When but a single target is in use the truck and track may be 
dispensed with and the target frame supported by posts set in 
the ground, but when several targets are to be used at the same 
time the truck and track feature will be found to save much 
tinie, as any target may then be drawn back to the firing point, 
examined, marked, scored, and pasted without waiting for the 
fire to cease at any other firing point or without delaying the 
fire at any other points. Plate 69 shows plan for six targets. 
106191°— 17 16 



242 



MACHINE-GUN FIRING MANUAL. 



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MACHINE-GUN FIRING MANUAL. 243 

270. Distance. — The distance from the firing point to the 
target is 27f yards (83 feet 4 inches), the only range at which 
known distance firing is held. At this distance the intercept of 
1 mil is equal to 1 inch. The range measure is taken from the 
center of motion of the gun to the target. For example, with 
a tripod mount, this is the pintle, with a barrel rest, the point 
of support near the muzzle. 

271. Peotection foe Maskers. — While firing is in progress, 
the markers remain in rear of the firing point ; hence no pits 
or other special measures for their protection are required. 

272. Interval Between Targets. — When practicable, the 
interval between targets should not be less than 10 feet. 

273. Telephone Service. — No telephone service is needed 
except when local conditions require communication by wire 
between range and some other locality, such as the camp or 
garrison. 

CLASS B EANGES-. 

274. Class B Range. — Certain extensive reservations in the 
United States and the Philippine Islands will furnish ample 
and suitable ground for combat firing. At times extensive tracts 
of unoccupied land or land from which the crops have been har- 
vested may be rented near the post. At other points where 
leased tracts are at the disposal of the garrison for purposes of 
target practice or maneuvers, facilitates for combat firing can 
probably be found. Any ground suitable for maneuvers will 
also be suitable for combat firing, if the safety of the neighboring 
inhabitants be taken into consideration and provided for. 

Tracts that have been set aside as permanent class B ranges 
may be improved by the construction of permanent shelters for 
the markers and pitmen, which should be made inconspicuous. 
Otherwise these ranges should be kept in the natural state, but 
changes made to facilitate the practice or to save labor from 
year to year should be such as not to provide assistance to those 
under instruction. 
^ For methods of determining danger zones, see paragraph 255. 



244 



MACHINE-GUN FIRING MANUAL. 




MACHINE-GUN FIRING MANUAL. 245 

RANGE REGULATIONS. 

275. The director is the personal representative of the com- 
manding officer. He should be, when practicable, a field officer, 
and will have general supervision of the firing and of the target 
range during the practice season. He will not supervise the 
details of the instruction of the companies practicing on the 
range, but will maintain order, regulate the distribution of 
ranges and targets to organizations, prevent infractions of regu- 
lations, and in general assist by every proper means to secure 
efficient and accurate service from the working force of the 
range. 

He will see that all necessary precautions are taken for the 
safety of the markers and such spectators as may be present. 

In the performance of his duties he — 

1. Prepares a progressive course of instruction and submits 
same to the commanding officer for his action. 

2. Requests the detail of suitable officers to act as umpires, 
range officer, and recorder. 

3. Takes steps to secure a sufficient number of large scale 
contoured maps of the class B range. 

4. Causes the umpires to prepare problems in accordance with 
the course of instruction as approved by the commanding officer, 
and within the limits of the range available, to select the ground 
on which these exercises are to be fired. 

5. The problems having been prepared, he causes them to be 
submitted to the range officer and requires him to make an 
estimate of the kinds and amounts of target material required 
for these problems, and to submit timely requisition for same. 

6. Requires the range officer to have constructed the neces- 
sary shelter for markers, lines of communication, etc., and to 
have the range prepared for the exercises according to the 
schedule. 



246 MACHINE-GUN FIRING MANUAL. 

7. Requires the umpires to prepare a detailed schedule 
showing — 

(a) The day or days on which each problem is to take 
place. 

(&) The organizations or subdivisions which are to par- 
ticipate. 

(c) When, where, and to whom each organization or sub- 

division will report for participation in each ex- 
ercise. 

(d) Details as to equipment, ammunition, uniform,, etc., 

required for each exercise. 

8. Requires copies of this schedule to be furnished to the 
commanding officer, range officer, recorder, each umpire, and 
each organization that is to participate. 

9. Requires the range officer to prepare, in accordance with 
this schedule, a list of men needed for duty on the range from 
day to day as — 

Foreman. • Range guards. 

Markers. Laborers, etc. 

Agents of communication. 
This list, after approval, is submitted to the commanding 
officer. 

10. During the period covered by the schedule of exercises, 
he is charged with seeing that the instruction is thorough ; that 
the schedule is carried through without friction, waste of time, 
or unnecessary delay ; that proper safety precautions are taken ; 
and that the records and reports are properly kept and rendered. 

270. The recorder acts as an adjutant for the director. He 
is also charged with the duty of keeping the records of the | 
exercises, and of computing such statistical data, theoretical 
standards, etc., as may be required by the umpires. 

He is provided with the necessary clerical assistance. 

277. The Range Officer. — The duties of the range officer 
are to prepare the targets, to superintend their placing and 
manipulation, to see that the range is safe, and where neces- 



MACHINE-GUN FIRING MANUAL. 247 

sary to post range guards to prevent persons from entering the 
area of fire ; to record and report the results of firing. 

Every precaution will be taken to provide for the safety of 
the markers, target men, and others whose duties require them 
to be anywhere within or near the area of fire. When it ap- 
pears to be necessary, a point which will be continually in 
view of the officer or noncommissioned officer in charge of 
the firing line throughout the exercise will be selected from 
which to display the danger signal. This point will be known 
to all engaged in the firing. No firing of any kind will be done 
while the danger signal is displayed. Should the danger sig- 
nal appear while an exercise is in progress the command will 
be halted and all firing and movement will cease. When the 
danger signal is removed the exercise will be resumed. 

278. Officers in charge of class B ranges should understand 
the construction of field targets, the manner in which they are 
assembled, and the details of their operation. There should 
be a contoured map of the range on which is shown the location 
of all pits and of all permanent or semipermanent telephone 
or buzzer lines ; they should be thoroughly familiar with the 
topography of the range and should be prepared to give advice 
as to the location of targets and their manipulation, and* to se- 
lect the terrain for problems when required to do so. 

Range officers should be furnished, a week in advance, with 
a schedule showing the nature of the work to be conducted. 
They should be given timely information as to changes in the 
schedule or in any particular firing exercise. 

When more than one problem is to be conducted in the same 
locality, the range officer should site the problems so as to 
prevent the fire of one becoming dangerous to the other. 

The range officer usually is furnished with a permanent detail 
of such enlisted foremen, artificers, laborers, etc., as are neces- 
sary. 

279. The Umpires, under the supervision of the director, 
are charged with the duties of preparing the problems, direct- 



248 MACHINE-GUN FIRING MANUAL. 

ing the range officer as to the arrangement and manipulation of 
targets for these problems, conducting the problems, observing 
the solutions of the problems, arriving at judgments as to the 
correctness of the solutions, and, based upon those judgments, 
delivering critiques. When required, they furnish the recorder 
with a -written synopsis of the critique. 

280. Use of Devices fob Determining Force and Direc- 
tion of Wind. — Anemometers, wind clocks, and other instru- 
ments, and flags, vanes, or streamers for determining the force 
and direction of the wind will be allowed on the range during 
instruction practice, but not during qualification firing. 

281. Dress and Equipment. — In all classes of firing the serv- 
ice uniform and service hat will be worn, the coat may be 
omitted when authorized by the post commander. 

For combat practice, the service uniform for field duty will 
be worn (see tables of occasions, Uniform .Regulations), to- 
gether with such field equipment as the commanding officer may 
prescribe as one of the conditions of the exercise. 

Officers will, when firing, wear the same uniform and equip- 
ment as the men. In conducting combat firing exercises officers 
will be equipped with field glasses and pistols ; sabers will not be 
worn. 

282. Qualification Test. — This is for two purposes : First, 
to afford the soldier an object lesson of his progress ; second, to 
obtain a record by means of which the soldier may be graded in 
awarding insignia and increased pay. The rules for the qualifi- 
cation test must be fixed and be applicable to all alike. These 
rules must be strictly observed by all, and scores must be re- 
corded accurately. 

In this practice coaching of any nature is prohibited. Each 
firer must make his correction as a result of his own observa- 
tions. After a soldier has taken his position at the gun no per- 
son shall render or attempt to render him any assistance except 
as provided for in the regulations prescribing the test. 

283. Field Glasses. — Officers and enlisted men will be 
allowed and encouraged to use field glasses. 



MACHINE-GUN FIRING MANUAL. 249 

281. Scoring. — The record of the score from which classi- 
fication will be made will be kept at each firing point by a non- 
commissioned officer who will be assigned, except at a one-com- 
pany post, to a point where his own company is not firing. The 
scoring will be closely supervised and the record verified by a 
company officer. Scores will be recorded on the range with pen- 
cil on sheets prepared for that purpose. 

A separate sheet will be kept for each man firing, and as soon 
as the man's score at any range is completed the scorer will sign 
the sheet and the company commander will take it up, initial it, 
and keep it in his personal possession until the scores are 
entered on the company target record. This entry is made by 
the company commander. 

285. The company target record will be kept in the personal 
possession of the company commander and not allowed in the 
hands of an enlisted man from the beginning of the record prac- 
tice until the required reports for individual known distance 
practice have been rendered. 

All entries in the company record will be made in ink, and no 
corrections or alterations will be made except by the company 
commander, who will initial each correction. 

The board for the examination of men for classification will 
accept the company's record of individual known distance prac- 
tice for that part of the qualification test. 

286. Noncommissioned Officer in Charge of Targets. — 
A competent noncommissioned officer, with such assistants as 
the post commander may deem necessary, will be detailed per- 
manently during the target season in charge of arrangements at 
the targets. 

He will be under the direction of the range officer and will be 
responsible for the efficiency and discipline of the target details. 
It will be his duty to see that targets are ready for the firing de- 
sired and that all targets are serviceable ; also to see that as the 
target details report they are provided with the proper flags, 
paste, pasters, etc. 



PART VI. 

CHAPTER I. 
RECORDS AND REPORTS. 

287. The following are required:* 

1. A performance record for each gun. 

2. A record of individual known distance, record firing, and 
qualification tests. 

3. Record of combat firing. 

4. The report of individual known distance practice. 

5. The report of individual qualification tests. 

6. The report of combat firing. 

288. The performance record for each gun. — There will be 
kept a daily record of all firing, showing the lot of ammunition 
used, the number of rounds fired from each barrel, and the gun 
adjustments. This record will show any parts replaced and 
any troubles or jams which occurred during the day's firing 
with a note of how these troubles were reduced. This daily 
performance record will be kept, if possible, with the gun at 
all times. 

289. The record of individual known-distance record firing 
and qualification test consists of a separate sheet for each indi- 
vidual firing the known-distance course. On these sheets are 
entered the results of the qualification test as follows : 

A. By the company commander. Known-distance record firing:. 
(a) Scoring spaces struck in — 
Group 1. Group 3. 

Group 2. Group 4. 

Total scoring spaces struck. 
250 



MACHINE-GUN FIRING MANUAL. 251 

(b) Time of firing (excluding time out for jams). 

(c) Time out for jams (excluding those due to broken 

parts. 
(cl) Total time (sum of "b" and "c"). 
(e) Score. 
B. By the examining board for final classification (par. 131). 
The percentage made in each of the following subjects : 
Materiel. 

Determination of the range. 
Sight setting and recognition of targets. 
Field firing. 
Total. 

General average (including known-distance record firing). 
Final classification. 
The company commander is the custodian of this record, blank 
forms for which will be furnished by The Adjutant General of 
the Army. 

290. The record of combat firing in each company contains 
the statement of each problem or exercise used and the statistical 
data and synopsis of the critique pertaining to each unit par- 
ticipating in such problem. 

The custodian of these records is the company commander. 
No blank form is furnished for this purpose. 

291. The report of individual known-distance prac f ice is 
rendered by the company commander to the regimental com- 
mander, or in the case of special organizations to the command- 
ing officer of the unit to which attached as soon as practicable 
after the completion of the individual known-distance practice 
(par. 110). 

This report consists of a list showing the scores of officers and 
enlisted men who have made 65 per cent or over in the known 
distance record firing. 

No blank is furnished for this report. 



252 MACHINE-GUN FIRING MANUAL. 

292. The report of the individual qualification test is made 
by the company commander at the conclusion of the test and will 
include : 

(a) The names of officers and enlisted men rated as expert 
rifleman, machine gun; sharpshooter, machine gun; and marks- 
man, machine gun. 

(b) The percentages made by each in all of the prescribed sub- 
jects. 

( c ) The general average of each officer and man. 

The data is taken from the record of individual known dis- 
tance record firing and qualification test. 

The Adjutant General will furnish the necessary blanks 
for this report. 

293. The report of combat firing is rendered by the organi- 
zation commander, through military channels, to the division 
commander. 

This report consists of two parts. Part I is based upon the 
company records of combat firing. It will be in narrative form 
and will include — 

(a) A general statement as to the combat firing of each or- 
ganization. 
, (b) The complete statement of all problems used. 

(c) Recommendations for improvements in the course of com- 
bat firing. 

Part II is the report of the commanding officer upon the record 
combat firing problems, Chapter V, paragraph 188 and iD eludes — 

(a) A complete statement of the problem. 

( b ) A statement as to the manner of its execution. 

(c) The complete statistical data. 

{d) Notes on the critique of the problem. 

(e) Such comments as may be deemed pertinent. 



MACHINE-GUN FIRING MANUAL. 253 

CHAPTER II. 
CLASSIFICATION, INSIGNIA, AND EXTRA COMPENSATION. 

294. Classification applies to officers and enlisted men. 

All officers and men belonging to machine-gun organizations 
and who join prior to known distance practice will take that 
practice except as noted in paragraph 4. 

295. Grades of Machine-Gun Men and Basis of Quali- 
fication. — Individuals of a machine-gun organization are graded 
according to the proficiency exhibited in the qualification test 
as expert rifleman — machine gun, sharpshooter — machine gun, 
marksman — machine gun, and unqualified. 

The unqualified class includes, in addition to the men who did 
not make the required percentage for qualification as marksman 
or better, all those men who are borne on the rolls of the 
organization and who have not taken the qualification test. 

The individual qualification test (par. 131 et seq.) is arranged 
on a percentage basis and is so designed that with care in 
instruction a soldier with an average education and some 
machanical ability can satisfactorily pass the test. 

INSIGNIA. 

296. Classes. — To each officer and soldier qualifying for 
the first time as expert rifleman — machine v gun, sharpshooter — - 
machine gun, and marksman — machine gun, certain insignia indi- 
cating their skill in marksmanship will be issued. In case of 
loss or damage new issue may be made as provided for in 
paragraph 298. 

297. Machine-Gun Men's Insignia, (a) Marksman's pin. — 
To marksmen, when first qualifying as such, will be issued a 
marksman's pin. A soldier having qualified as a marksman may 
wear this pin as long as he continues to draw the increased pay 
for that qualification. 



254 MACHINE-GUN FIRING MANUAL. 

( b ) Sharpshooter's badge. — To the sharpshooter a silver badge 
will be issued. For the first qualification in this grade the badge 
will consist of a pin and a cross ; the soldier having once qualified 
as a sharpshooter may wear the badge while he is entitled to 
draw increased pay for that qualification. To those who have 
qualified as sharpshooters for three years, not necessarily con- 
secutive years, nor in the case of enlisted men in the same en- 
listment, a silver bar will be issued on which the three years of 
their qualifications will be indicated, and this will be attached 
to the badge between the pin and the cross. For each additional 
three years of qualification an additional bar will be issued and 
each in succession attached below the one previously supplied 
and above the cross. 

(c) Expert rifleman's badge. — To the expert rifleman will be 
issued a silver badge. The soldier having qualified as an expert 
rifleman may wear the badge while he is entitled to draw the 
increased pay for that qualification. To those who have qualified 
as expert rifleman for three years, not necessarily consecutive 
years, nor in case of enlisted men in the same enlistment, a silver 
bar will be issued on which the three years of their qualifications 
will be indicated, and this will be attached to the badge below the 
pin. For each additional three years of qualification an addi- 
tional bar will be issued and each in succession attached below 
the one previously supplied. 

298. Duplicates. — These insignia will become the property 
of the persons to whom issued. If they are lost by the owner 
or in transmission to him, or if they become unsightly from long 
wear, they may be replaced without cost to the owner. But in 
all cases the official certificate of the company commander to 
the effect that he has investigated the circumstances of the loss 
or damage and finds that no negligence can be imputed to the 
soldier will be required as evidence upon which to make the new 
issues. In case of loss claim must be made within 60 days from 
date of loss. Duplicates, if desired for use on separate coats, 
will be sold to those entitled to wear the insignia. 



MACHINE-GUN FIRING MANUAL. 255 

299. How Obtained. — Immediately after the close of the 
practice season the company commander will report by letter 
to the commanding officer the names of men in his organization 
who have made a new or renewed qualification. With this 
letter the company commander will submit a requisition for the 
required number of badges and bars. This requisition will be 
disposed of as any other special ordnance requisition. 

300. Extra Compensation. — The soldier will receive such 
extra compensation for qualification in machine-gun firing as 
may be authorized by law and regulations. 

Immediately after the completion of the qualification test, 
the names of men who qualify in the various grades for which 
extra compensation is awarded will be published in orders. 
These orders will be issued by commanders empowered by regu- 
lations to issue orders for the appointment and promotion of 
noncommissioned officers, or in exceptional cases by higher com- 
manders, upon receipt of properly authenticated evidence as 
to qualification, and will show the date of actual qualification 
from which the soldier is entitled to additional pay. 



PART VII. 



COURSES FOR ORGANIZATIONS NOT IN THE REGULAR SERVICE. 

301. The course of known-distance practice and combat 
training for the National Guard, Federal Reserves, Volunteers, 
and all other organized Federal forces not in the Regular serv- 
ice, will be, as far as practicable, the same as prescribed herein 
for the Regular Army. 

Local conditions alone determine the manner and amount in 
which the complete courses must undergo modification. In 
modifying the courses, consideration is given to the state of 
training found in the organization, to the local facilities for 
range practice and maneuver, to the total time available for 
training and to the available ammunition allowance. 

The standards for individual and organizational classification 
and for the issue of insignia will be the same as prescribed 
herein for the Regular service. 

When local conditions are such as to prevent the holding of 
the prescribed tests for an organization or for the individual 
thereof, then there will be entered on the report the remark : 
"Test not possible under local conditions. Individuals (or 
* organizations ' or ' organization and individuals ' ) not classi- 
fied." 
25G 



APPENDIX. 



SYLLABUS OF COMBAT TRAINING. 

Combat training may be divided into several classes. 

First. Those exercises designed to train individuals or to give 
practice in teamwork. These exercises are classed as individual 
and collective, the collective exercises being for squads, platoons, 
companies, etc., and either including or excluding the transport. 

Second. Those exercises classed as technical exercises and fire 
problems and designed to give practice in technique alone, or to 
give practice in the application of technique to the accomplish- 
ment of a given tactical mission. 

Third. According to the instructional methods, such as map 
problems, terrain exercises, tactical walks, landscape practice, 
field firing exercises, etc. 

The machine-gun organization has but one means of fighting — 
fire poicer. 

The combat training of the organization has for its ultimate 
object the making of the organization as a whole, and of each 
of its subdivisions when called upon to act alone — a smoothly 
working team. The leaders of these teams should have their tac- 
tical judgment cultivated to such a point that they know almost 
intuitively when, where, and how to apply the fire power at their 
command. 

The subordinate members of the teams must have the technical 
skill requisite to produce the maximum fire effect in accordance 
with the directions of their leaders. 

In taking up any particular phase of training, knowledge of 
certain fundamental principles and skill along certain basic lines 
106191°— 17 17 257 



258 MACHINE-GUN FIRING MANUAL. 

must be assumed. In the case of combat training, therefore, it is 
assumed that the gun crews are trained in marksmanship as 
individuals and as teams, and that the individuals of the trans- 
portation and supply units of the organization have the requisite 
technical skill to perform their duties properly. 

Combat training has for the leaders a double purpose. 

In the first place, it serves as an indication of the leader's 
ability as an instructor, i. e., the discipline and technical skill 
displayed by his subordinates, or the absence of these qualities, 
may be taken as an index of the manner in which a leader has 
trained his subdivision. Or, perhaps, such indications may point 
to the fact that certain leaders have no aptitude as instructors 
that certain subordinates have no aptitude for or have not been 
under instruction long enough to attain facility in their duties 
that insufficient time is allotted for the training of certain sub 
divisions, e. g., squads, gun crews, platoons, transport personnel, 
etc. ; or that the responsibility of certain leaders for the train- 
ing of their units is such in name only, their function in this re 
spect having been usurped by higher authority. 

In the second place, combat training serves as a means for de- 
veloping in leaders the functions of leadership. It teaches them. 
in their respective spheres, how to make use of the technical 
skill of their subordinates, how to coordinate the work of the 
various individuals and subdivisions, and how to apply this co- 
ordinated skill in compliance with the orders or directions re- 
ceived from higher authority. 

To carry this instruction to a logical conclusion, not only 
should it be continued until the leader has attained the requisite 
facility in the performance of his duties in combat, but it should 
be such as will assure the maintenance of this facility. 

Training is intensive until the required standard of proficiency 
is attained. Thereafter individuals or teams are given only such 
practice as will enable them to maintain that standard. 

It is important to avoid training or practice to the point where 
teams or individuals become " stale." 



MACHINE-GUN FIRING MANTJAL. 25& 

That the maximum instructional value may accrue from com- 
bat training, it is necessary that any scheme of instruction be 
progressive. The subdivisions of any "unit must be trained indi- 
vidually before an attempt is made to train them collectively. 
Thus the squad leader, the gunner, and the gunner's assistants 
are trained as individuals before their combined efforts are co- 
ordinated in the training of the gun squad. The platoon leader 
is trained as an individual and the gun squads as individual 
teams before combining them for platoon instruction. The same 
principle applies to the training of the higher units of organ- 
ization. 

Combat training then includes : 
Individual instruction of — 

Gunners. 

Squad leaders. 

Section leaders. 

Guides. 

Platoon leaders. 

Company commanders. 

Agents of communication. 

Scouts. 

Range takers. 

Leaders of transportation and supply units. 

Leaders in the combined action of several companies. 
Collective instruction of — 

Gun squads. 

Gun platoons. 

Transportation and supply units. 

Gun companies. 

Two or more gun companies acting together. 
The training of these individuals and units includes the fol- 
lowing : 

gun nee s. 

1. Target designation to the point where the gunner can under- 
stand a terse designation of an obscure objective or aiming 



260 MACHINE-GUN FIRING MANUAL. 

point and then lay his piece according to the fire order of his 
squad leader. He should also be able to lay his piece properly 
on a target designated by a sketch or range card. 

2. Methods of fire against various objectives as — 

Straight and irregular lines. 

Columns. 

Moving targets. 

Aircraft. 

Artillery. 

Machine guns. 

Cavalry. 

Trenches. 

Trains. 
This training continues to the point where the gunner can be 
depended upon to secure the maximum material effect when 
given a correct fire order. Also he should be able to secure this 
maximum effect in the absence of his leader at ranges under 600 
yards. 

3. Adjustment of fire, in so far as the gunner is concerned, 
ordinarily consists of firing strictly in accordance with the di- 
rections of his leader. 

In cases where the gun is left temporarily in position with a 
single man as its crew, this man, in his capacity of gunner, must 
understand the principles and practice of ranging and the use 
of the battle sight. Such fire ordinarily is confined to the 
shorter ranges, and hence skill in the estimation of distances 
beyond 600 yards is of questionable value. 

The gunner must understand adjustment to the extent of — 

(a) Firing as he is told when acting under a leader. 

(b) Skill in ranging at distances less than 600 yards. 

(c) Skill in estimating distances less than 600 yards. 

( d ) The use of the battle sight. 

(e) Sight setting of his gun for any given range. 

4. Fire discipline, for the gunner, consists in the subordination 
of his will to that of his leader. 



MACHINE-GUN FIRING MANUAL. 261 

It involves an intelligent understanding of fire orders, and the 
technical skill involved in their execution. This includes the 
requisite marksmanship and mechanical skill with his gun. 

It is then that state of mind which places his knowledge and 
skill at the disposal of his leader — to be used promptly and 
efficiently as the latter may dictate. 

SQUAD LEADEES. 

1. Target designation to the point where they can understand 
a terse description of an obscure objective or aiming point and 
can, in turn, describe their portion of the objective in terms a 
trained gunner can understand. 

2. Methods of fire to the point where, in compliance with the 
fire order they have received, they are to translate their order 
into quick, clear, and accurate commands. 

3. Adjustment of fire, for the squad leader, involves: 

(a) Skill in estimating distances under 600 yards and in 
utilizing the combined estimates of the members of his squad at 
distances under 1,000 yards. 

( b ) Skill in the use of the range finder and mil scale. 

(c) Such a knowledge of sights (tangent and telescopic) 
that he can give his gunner the correct sight setting. 

(d) Use of the field glass in target finding and the observa- 
tion of fire. 

(e) Ranging. 

(/) Sight setting of his gun for any given range. 

4. Fire control to the point where they quickly grasp the 
spirit of a fire order and translate it promptly into commands 
to their squads. It includes also the habitual maintenance of 
fire discipline within the squad. 

5. Communication to include proficiency in the — 

(a) General service code. 

(&) Semaphore code. 

(c) Hand and arm signals. 

id) Whistle signals. 

(e) Letter codes. 



262 MACHINE-GUN FIRING MANUAL 

6. Reconnaissance and sketching includes — 

(a) Training as patrol leader. 

(b) Route sketches. 

( c ) Position sketches. 

(d) Landscape sketches. 

7. Selection and occupation of positions as applied to a sin- 
gle squad. 

8. Fortification and concealment as applied to a single squad. 

9. Tactics, fundamental principles as applied to single squad 
acting in platoon or alone. 

10. Ability* to instruct the members of the gun crew in all 
their duties. 

11. Maneuver of the squad. 

GUIDES. 

1. The duties of the squad leader must be familiar to the 
guides. 

•2. Fire control to the point where they can enforce strict and 
prompt obedience to the orders of the platoon leader. 

3. Communication between the platoon and the company com- 
mander is a duty of the guide when no agent is provided for 
that purpose. 

4. The duties of platoon leader are not an immediate require- 
ment of the guide. The events of an active campaign, however, 
may place the guide in command of a platoon at any moment, 
and hence he is considered as a platoon leader in the making. 
Advantage is taken of every opportunity to bring about his per- 
fection in these duties. 

PLATOON AND SECTION LEADERS. 

1. Tactics. — A thorough knowledge of the fundamental prin- 
ciples for a platoon acting alone or as a part of the company. 
This includes the maneuver of the platoon. 



MACHINE-GTJN FIRING MANUAL. 263 

2. Fire control to the point where they can grasp the spirit of 
the company commander's order and translate it quickly into 
complete and accurate commands to the platoon. 

3. Technique. — Knowledge and practice to be complete and 
thorough. 

4. Theory of fire. — Possess a thorough knowledge of the fun- 
damental principles and the ability to apply these principles 
to concrete cases. 

5. Instruments. — This includes a thorough knowledge and 
practical skill in the use of — 

Field glasses. 

Range finders. 

Sights, all varieties. 

Mil scale. 

All devices used for fire control — 

Prismatic compass. 

Clinometer. 

Level. 

6. Reconnaissance and sketching. — Thorough knowledge and 
practical skill. 

7. Communication. — Practical skill in — 

General Service Code. 
Semaphore Code. 
Hand and Arm Signals. 
Whistle Signals. 
Letter Codes. 

8. Fortification and concealment. — Types of cover for single 
guns and the combination of the emplacements of the guns of 
the platoon in conformity with the terrain and the tactical 
situation. 

9. Ability to instruct squads and all the individuals in the 
platoon. The instruction of the guide in the duties of platoon 
leaders is the duty of the captain. 

10. The duties of company commander pertain to platoon 
leaders to the extent that they are company commanders in 



264 MACHINE-GUN FIRING MANUAL. 






the making. Platoon leaders must be competent to fill the com- 
pany commander's place in an emergency. 

COMPANY COMMANDEES. 

1. Tactics. — The company commander's knowledge of tactics 
must be thorough. It must include not only the handling of 
his organization in compliance with orders, but also the ability, 
when called upon, to offer sound advice to the regimental or 
other commander as to the tactical employment of the com- 
pany. 

This knowledge must be supplemented by sufficient practice 
to give the company commander unquestioned skill not only 
in the issuing of the regimental commander's order to the 
machine-gun company but also in executing that order. This 
includes the maneuver of the company. 

2. Technique. — The company commander's technical knowl- 
edge should embrace the entire field of machine-gun work. 

3. Instruments. — A practical working knowledge of all the 
instruments in use in the company is required of the company 
commander. 

Skill is required only in the use of those instruments with 
which he exercises fire direction and control : 
Field glass. 
Prismatic compass. 
Clinometer. 
Mil scale. 

4. Theory of fire. — The company commander's knowledge of 
the theory of fire should be profound. 

5. Fortification and concealment. — The company commander's 
knowledge of this subject must be complete and thorough. It 
includes not only the details of construction and the expedients 
that may be employed for single guns but also embraces the 
use of guns in combination and the placing of his guns in con- 
formity to a given tactical mission on a given terrain and in 
cooperation with the other arms. 



MACHINE-GUN FIRING MANUAL. 265 

His skill, in this phase of his work, must be developed to the 
point where he can view the situation through the eyes of 
a higher commander ; decide promptly upon the type of cover 
to be used and the position or positions for each gun ; and, then, 
without undue delay, embody this decision in a clear-cut order 
to his organization. 

6. Ability as an instructor. — The company commander is pri- 
marily an instructor of platoons and the supervisor of all other 
instruction in the company. In addition to this, however, he 
must be able to teach any of his subordinate instructors how 
to train any of the individuals under their tutelage. Further- 
more, he must train the platoon leaders to act as company 
commanders. 

7. The command of provisional machine-gun battalions should 
be a matter of study on the part of the company commander 
and he should be able to issue tactical and fire orders to such 
a unit. 

8. Communication. — 

Letter codes. 

Hand and arm signals. 

Whistle signals. 

COMPANY SPECIALISTS. 

The specialists in combat are the — 
Range takers. 
Scouts and 

Agents of communication. 
The training of all should be along similar lines and would 
include — 

1. Scouting and patrolling. — This includes not only the ordi- 
nary tactical reconnaissance demanded of a patrol, but also the 
selection of machine-gun positions and the selection and mark- 
ing of the routes thereto. Marked skill in recognition and 
designation of targets is demanded of these men. 



266 MACHINE-GUN FIRING MANUAL. 

2. Instruments. — The use of the range finder, field glasses, and 
mil scale. 

3. Communication. — 

General Service Code. 

Semaphore Code. 

Hand and arm signals. 

Whistle signals. 

Letter codes. 

Duties of messenger. 
Also skill in the use of any other means of communication 
that may be supplied as part of the equipment of the organiza- 
tion, such as lanterns, heliographs, buzzers, field telephones, etc. 

4. Sketching. — Route, position,' and landscape sketches and 
range cards. 

LEADEKS IX SECOND ECHELON. 

In the second echelon of a machine-gun company are found 
the following subdivisions : 

(a) A unit which, for purposes of identification, is termed 
the " Support " and whose function it is to replace casualties 
in the firing line and to keep that firing line supplied with 
ammunition. 

(b) A unit in charge of the transportation pertaining to the 
firing line. 

(c) A unit in charge of the transportation pertaining to the 
support and whose function is to seek a new supply of ammuni- 
tion when necessary. 

(d) The supply section or field train. 

The leader of the field train will rarely if ever have to arrive 
at a tactical decision upon his own initiative. Usually these 
wagons will march with the field train of the regiment and 
under the orders of a quartermaster. Hence this unit need not 
be considered in connection with combat training. 

The leader of the support should be trained as a platoon 
leader. 



MACHINE-GUN FIRING MANUAL. 267 

The leaders of the two transportation units, noted above 
I under (b) and (c), should be trained in — 

1. Maneuver of their subdivisions in compliance with tactical 
orders. 

2. Reconnaissance of routes and the following of routes pre- 
viously reconnoitered and marked. This includes map reading. 

3. Use of cover in connection with the selection of routes and 
positions. 

4. Communication — 

General service and semaphore codes. 
Hand and arm signals. 
Whistle signals. 
Letter codes. 

LEADEKS OF PROVISIONAL BATTALIONS. 

This is included in the training of the company commander. 

In all of this individual training it should be borne in mind 
that not only should the endeavors of instructors be directed 
toward perfecting the individuals in the duties pertaining to the 
positions they are actually filling, but also toward fitting each 
individual to take up the duties of higher grades. 

In this connection it is deemed important that there be at 
least three understudies for each position on the firing line. The 
manner in which this is accomplished is of little moment. 

The following outline shows one system that meets this 
requirement : 

Position. Understudies. 

Captain Lieutenants. 

Platoon leaders First sergeant. 

Guides. 

Section leaders. 
Guides Section leaders. 

3 squad leaders. 



268 MACHINE-GUN FIRING MANUAL. 

Position. Understudies. 

Section leaders .—9 squad leaders. 

9 gunners. 

Squad leaders 3 gunners. 

12 loaders. 
9 prives. 

Gunners , 24 privates. 

Privates of gun crew All reservists except those whose 

adaptability is more to duties 
pertaining to supply, adniinistra- 
• tion, or transportation. It should 
be the endeavor to discharge all 
such reservists with the qualifica- 
tion of " marksman " or better. 

Company specialists All. officers and noncommissioned 

officers must be competent to act 
as range takers. The understudies 
for the scouts and agents of com- 
munication are taken from the 
company at large and the selec- 
tion naturally falls upon indi- 
viduals who have the necessary 
aptitude for such work. A proper 
proportion of reservists also 
should be trained to these duties. 

SQUADS. 

1. Drill. — This includes the mechanism of the service of the 
piece, the mechanism of close-order movements, both with and 
without the transportation, and the mechanism of extended 
order. This to include the squad acting alone and in platoon. 

2. Maneuver in the zone of hostile fire. — This training to be 
in the nature of concrete problems. A movement is required 
over a given piece of ground and under certain stated tactical 
conditions. The troops (Infantry or Cavalry), with which the 



MACHINE-GUN FIRING MANUAL. 269 

machine-gun squad is acting, must be assumed or outlined if not 
actually represented, as must also the other elements of the 
machine-gun company in all problems in which the squad is 
assumed to be in platoon. 

Squad problems not only include those in which the squad 
leader is acting alone, wherein the squad leader must make his 
own decision as to formation, movement, and objective, but they 
also include problems in which the squad is a part of a platoon 
acting under the definite orders of the platoon leader. 

In order to insure proficiency in the use and understanding of 
signals, these problems will frequently include the condition 
that the voice is inadequate for purposes of command. Not only 
must the squad be led by signals, but also the squad leader will 
receive his orders in a similar manner. 

The use of natural cover is an important feature of this 
training, as are also the adoption of formations that will conceal 
the identity of the machine-gun unit, and the maintenance of 
communication with the other elements of the command with 
which the machine-gun squad is acting. 

3. Reconnaissance and selection of positions. — While a squad 
leader usually is not called upon to perform these duties when 
his squad is acting as part of a company, they become an im- 
portant part of his duties when the squad is detached. 

This training is designed to give practice to the squad leader 
in using his personnel to assist him in the reconnaissance, in 
selecting positions in which the balance of the squad is to remain 
concealed while the reconnaissance is being carried out, and in 
controlling the squad by signals after the firing position has 
been selected. 

The actual selection of the firing position depends upon the 
individual training of the squad leader. 

4. Occupation of positions. — The occupation of positions is 
the same no matter whether the selection of the position is made 
by the squad leader or by the platoon leader. 

In general, it may be said that there are two ways in which 
a position is occupied. One is the case in which an emergency 



270 MACHINE-GUN FIRING MANUAL. 

has arisen which demands that the guns be placed in position 
and open fire with the least practicable delay. The other is the 
case in which the situation permits greater deliberation. 

The training should include both these cases. 

Special attention is given to the use of cover. 

5. Fortification and concealment. — This includes types of cover 
to be used alone or in infantry trenches ; hasty intrenchment 
and deliberate preparation of permanent field works and the 
evolution of the latter from the former. For the squad leader it 
includes also the cultivation of his judgment as to the type of 
cover to be constructed in the time available. 

6. Target recognition. — This includes not only the actual 
search for animate targets, but also the decision as to what por- 
tion of the field of fire is to be covered by the gun. 

7. Registration of the field of fire. — This includes the use of 
the personnel in the preparation of range cards both for attack 
and for defense. 

8. Collection and computation of firing data. — This training in- 
cludes the use of the personnel, when time permits, to collect the 
data as to ranges, atmospheric conditions, etc. Otherwise the 
squad leader makes his own estimates as to these values. 

When the squad is acting alone the computation of the data 
is a function of the squad leader. Based upon the figures deter- 
mined by his squad, or upon his own estimates, he decides upon 
what elevation and deflection is to be used ; whether or not an 
aiming point is required and, if so, what that point shall be ; and 
the amount of searching to be used, if any. Upon the correct 
decision in these cases depends the accuracy of the fire, i. e., the 
number of hits that will be obtained per shots fired. 

He decides upon the kind of fire, rate of fire, method of distri- 
bution, and upon the amount of fire per unit area or unit front of 
the target. Assuming an accurate fire, then upon the correct- 
ness of these decisions depends the material or moral efficacy of 
the fire, i. e., the number of casualties produced in the rarks 
of the enemy in a unit of time, or the degree to which it aids 
in the attainment of fire superiority. 



10. Fire orders. — 

11. Adjustment of flre- 

12. Fire for effect. — 



MACHINE-GUN FIRING MANUAL. 271 

It remains for these decisions to be communicated to the 
squad in the form of a fire order. 

9. Target designation is a subject which calls, essentially, 
for individual training. In this connection, however, it is con- 
sidered important that every member of the gun crew know the 
location and extent of the target. Thus any of them could take 
the place of the gunner or squad leader at any time without lead- 
ing to confusion. 

This training is directed toward the 

perfection of the teamwork be- 

■ > tween squad leader and gunner. 

Their understudies also are given 

this practice. 

13. Tactics. — The training included under the 12 subheads 
enumerated above is entirely technical in its character. It still 
remains to give the squad practice in applying their knowledge 
and skill in technique, marksmanship, and mechanism in the so- 
lution of tactical problems. 

Such problems are called " fire problems " and they are de- 
signed to give practice in all the probable tactical phases of com- 
bat such as outposts, advance and rear guards, attack, defense, 
delaying actions, withdrawals,' attack and defense of convoys, 
etc. 

GUN PLATOONS. 

The technical and tactical training of the gun platoon is, with 
obvious modifications, along lines similar to those outlined 
above for the squad. 

TRANSPORTATION AND SUPPLY UNITS. 

These units are trained in — 

Maneuver, 

Supply (ammunition and replacement of casualties), 

Reconnaissance, and 

Communication 
in connection with assumed tactical conditions under which their 
firing line is acting. 



[-trained 



272 MACHINE-GUN FIRING MANUAL. 

THE COMPANY. 

The essentials of company combat training are a well- 
leader and well-trained subdivisions. With this as a foundation, 
it remains to perfect that nicety of teamwork whereby, under 
the properly framed orders of their leader, the subdivisions of the 
company act promptly, efficiently, and in concert for the accom- 
plishment of a common end. 

With obvious modifications, the tactical and technical details 
of this training is along lines similar to those outlined for the 
squad. 

PROVISIONAL BATTALIONS. 

The training of the battalion follows the general scheme here- 
tofore outlined for the companies. 

The scope of combat training.— Taking indidvidual and collec- 
tive training together, it is found that the following is the ag- 
gregate of the subjects embraced in a complete course in combat 
training : 

Related Subjects : 
Drill— 

Duties of personnel. 
Fire orders. 
Maneuver in the zone of hostile fire— 
Deployment — 

Into echelons. 

Of the firing line. 

The march into action. 

Selection and occupation of positions. 

Supply — 

Ammunition. 
Reinforcements. 
Communication — 

Methods employed to maintain — 
With superior headquarters. 
With subordinate units. 
With neighboring troops.* 
With troops which the guns are supporting. 



MACHINE-GUN FIRING MANUAL. 273 

Related Subjects — Continued. 
Communication — Continued. 
System of — 

Whistle signals. 
Hand and arm signals. 
Letter codes. 
General c ^rvice code. 
Semaphor code. 
Messengers. 
Reconnaissance — 
Tactical. 
Topographical — 
Routes. 
Positions. 
Landscapes. 
Fortification and concealment — 
Tactical. 
Technical. 
Training of leaders as instructors. 
Tactics. 
Theory of Fire. 
Use of Instruments : 
Range finder. 
Field glass. 
Sights — 

Tangent. 
Telescopic. 
Prismatic compass. 
Clinometer. 

Level or quadrant for elevations. 
Mil scale. 
Technique of Fire: 

Recognition and designation of targets. 
Determination of ranges. 
Adjustment of fire. 
Fire for effect. 

106191°— 17 18 



INDEX. 



Aiming and sighting drills. Part I, Chapter III. Paragraph. 

Distributed fire, practice in 48 

Elevating gear, verifying use of 46 

Elevating mechanism, use of 45 

Reloading 51 

Rate of fire dependent on rapidity with which piece is 

reloaded 51 

Use of dummy cartridges 51 

Searching fire, definition 47 

Practice in 47 

Mil unit of measure announcing amount of searching 

fire 47 

Searching with distribution 49 

Searching with distribution, diagonal 50 

Aiming tripod, use of, and description 165-166 

Ammunition, allowance for combat practice — Record 151 

Use of, in field-firing exercises 151 

Anemometers, use on range 280 

Barrel, new, to be used in overhead fire_ 128 

Sight setting for each to be determined before field firing 113 

Barrel rest, position of legs have important influence on uniform 

results 41 

Benet-Mercie gun: 

Light-type gun 11 

Position exercises 39 

Boards of officers for examination for classification 131 

Butts, artificial 259 

Hills as 260 

Canting the piece, demonstrating effect of 36 

Classification, definition of 294 

Grades of machine-gun men and basis of qualification 295 

Percentage required for different classes 131 

Clinometer, training in use of 58 

Clock system, target designation: 

Horizontal 90 

Vertical 91 

Coaching. 136-282 

Combat firing. Part III, Chapter I. 

Conduct of field firing exercises 171-182 

Information given out by umpire 172 

Range officials 171 

275 



278 INDEX. 

Combat firing — Continued. 

Conduct of field firing exercises — Continued. p , 
Umpire's critique — Paragraph. 

Basis of judgment 173 

Correcting errors at time when made 172 

Examples of form of critique 175 

Judging casualties : 180 

Judgment as to rates of impact 181 

Table giving rate at different ranges at different 

targets 181 

Table showing percentage of casualties depend- 
ing on volume of fire 182 

Use of table explained-- 182 

Standards set in table merely a guide 177 

Umpire's reference table, use of 176 

Machine-gun umpire's table 177-178 

Use of two tables combined 179 

Critique of field firing exercises 183 

Best given on ground immediately following exercise 187 

General discussion as to how conducted 183 

Personality of umpire important 184 

Points on which umpire might comment , 187 

Synopsis may be written 187 

Drill exercises — 

Adequate preliminary exercises necessary 160 

Method of instruction : . 162-164 

Aiming tripod, description . 166 

Use of 165 

Method of pointing our errors made 168 

Method of showing correctness or incorrectness of target 

designation 169 

Preparation of combat problems in trench warfare, night 

firing, and firing at aeroplanes __. 170 

Table showing theoretical effect of errors in determina- 
tion of range 167 

How to use table 167 

Field-firing exercise — 

Advance information, none to be given 152 

Ammunition supply, question of 151 

Limitations of 149 

Machine-gun units only participate 157 

Purpose 147-148 

Requirements in solution of brigade and division prob- 
lems 156 

Should be laid on unfamiliar ground 149 

Statements required 154 

Targets must present logical appearance. 150 

Time allowed by umpire to complete exercise 152 






INDEX. 277 

Combat firing— Continued. Paragraph. 

Fire problems : 137 

Construction of, and classes 145 

Statement of problem to be concise and simple 146 

General discussion 137 

Machine-gun commanders' problem, definition _ 147 

Defense 158 

Delaying action 158 

Firing at aeroplanes 158 

Firing on masked targets 158 

Firing with guns masked 158 

Night firing 158 

Rear guard 158 

Recontre 158 

Supporting attack 158 

Trench warfare 158 

That can be handled on class A and B ranges 159 

Tactical ability, how developed : 141 

Machine-gun organizations to serve as school for 

instructing other officers 141 

Responsibility of regimental and post commanders- 141 

* Training of machine-gun commander, in tactics 142 

In technique 143 

Should be progressive 144 

Types of 138 

For commanding officers 139 

For subordinate commanders 140 

Advisor in technical details 140 

Combat practice — Record i 188 

Allowance of 500 rounds per gun yearly 188 

Careful record to be kept 188 

Held after preliminary training : - 188 

Should contain essential features of fire training as range 

facilities will permit 188 

Critiques, how conducted 183-187 

Company and troop officers: 

Assisted by lieutenants, noncommissioned officers, and se- 
lected men 7 

Responsible for training of men and organizations 7 

Company target record: 

Entries made in ink 285 

Kept in personal possession of company commander 285 

Compensation, extra 300 

Danger signals '_! 264 

Department commander: 

Duties of 10 

Examines firing records 10 



27i INDEX. 

Department commander— Continued. Paragraph. 

Orders test firings at annual inspection 10 

Supervises instruction in machine-gun training of troops in 

his department . 10 

Determination of the range, the 59-81 

Definite method essential to accuracy , 59 

Methods of 59 

Estimating distances on the ground by eye 60 

Appearance of objects at different distances 63 

Collective estimating 73 

Exercises suggested _^ 74 

Simple and uniform system necessary 73 

System suggested 73 

Conditions when men or organizations may be con- 
sidered proficient- 75 

Daily practice necessary . 60 

Manner in which taught _ 6-1 

Exercises suggested 65-70 

Methods of 59 

Prone position habitual in combat 69 

Unit of measure 60 

Skill attained by training . 60 

Short distances 60 

On ground . 78 

By pacing of horse or men 78 

By use of tape or chain 78 

With engineering instruments 78 

From map : m 7X5 

By range finder^ 80 

By range estimators 81 

By sound 79 

From troops already engaged 77 

Value in examination for classification 131-133 

Elevating gear, exercises verifying use of 46 

Elevating mechanism, exercise in use of 45 

Equipment and dress on range 281 

Estimating distance. (See Determination of the range.) 

Examinations for classification 131 

Expert rifleman, percentage required to classify as 131 

Extra compensation 300 

Field glasses, training in use of 53 

Use on range to be encouraged 283 

Fine sight, not recommended 26 

Full sight, not to be taught 26 

Gage, for measuring shot groups . 99 

For measuring triangles 33 

General scheme, firing regulations 1 



INDEX. 279 

Paragraph, 
Ground, suitable for machine gun practice, procured by post com- 
mander 9 

Heavy guns, definition , 11 

Methods of sighting 27 

Indirect fire 11*5 

Individual field-firing test 136 

Assistant , 136 

Coaching : 136 

Cover 136 

Credits 136 

Value in examination for classification 131 

Individual known distance practice, value in examination for 

classification 131-185 

Individual qualification test for members of machine-gun organi- 
zations 131 

Examinations conducted by boards 131 

Subjects in which examined 131 

Determination of the range 133 

. Individual field firing test 136 

Individual known distance practice. . 135 

Materiel 132 

Sight setting and recognition of targets 134 

Insignia , 296-299 

. Classes 296 

Duplicates 298 

Expert rifleman's badge 297 

How obtained 299 

Marksman's pin . 297 

Replacing lost 298 

Sharpshooter's badge 297 

Instruction field firing __ : ,_■ 114 

General discussion 114 

Indirect fire - 116 

Night firing 129 

Arrangements made before dark 129 

Methods suggested 129 

Night firing box, description 130 

Use of 129 

Stake silhouetted in front of a night box 129 

When used , 129 

Overhead fire 124 

Instruction, individual. Part II. 

Nomenclature, use, care, and repair of machine guns anil 

accessories 11 

Automatic rifle, air-cooled gun 11 

Gas-operated guns 12 



280 INDEX. 

Instruction, individual — Continued. Paragraph. 

Nomenclature, use, care, etc., of machine guns, etc.^Con. 

Heavy and light type guns_ 11 

Highly specialized gas engines necessitating thorough 

familiarity _ 12 

Machine gun, water-cooled gun 11 

Recoil-operated guns 12 

Instruction in the mechanics of the gun 13 

Use of Ordnance handbooks and manuals as texts in in- 
struction . 13 

Instruction, scheme of, arrangement 2 

New and successfully applied methods to be reported 6 

Object of 1 

Instruments, use of 52 

Men to be thoroughly instructed- in instruments with which 

organization is supplied 52 

Training, part of garrison work 52 

Outline of 52 

Clinometer and hand level :__. 58 

Field glasses 53 

Mil scale 55 

Prismatic compass : 57 

Range finders 54 

Sights 56 

Interval between targets, machine-gun range 272 

Known-distance practice, definition of 94 

Distributed fire 105 

Fixed fire 104 

General remarks 96 

Individual known distance practice___ 97 

General scheme 97 

Instruction practice 98 

Holding '___ 99 

Scale of machine-gun ordinates at 1,000 inches from 

muzzle of gun 100 

Shot-group gauge 99 

Soldier should keep record of center of impact of 

each shot group :_, 99 

System to obtain the 500-yard ordinate 101 

Reloading : 98 

Known-distance record test 109 

List of men who made over 65 per cent to regimental 

commander -- 109 

Not to be fired on same day as instruction practice 109 

Rule and regulations for record practice, qualification 

course 110 



INDEX. 281 

Known-distance practice, definition of — Continued. Paragraph. 

Object of 95 

Preliminary practice on record target 108 

Table of sight settings for different guns 108 

Searching fire 106 

Searching with distribution 107 

Lewis gun 11 

Light type gun 11 

Position exercises, illustrated 40 

Uniform results dependent on position of legs of barrel rest 

and firer 41 

Lieutenants of companies, assist company commander in instruc- 
tion 7 

Light guns, definition 11 

Methods of sighting 27 

Lowest shot clearing mask in indirect fire . 122 

Machine-gun organization, to serve as school for instructing other 

officers 141 

Machine-gun practice, general supervision by post commander 9 

Machine-gun ranges (see Ranges, target, machine gun) 267-273 

Machine-gun umpire's table, description and use of 176 

Map, indirect fire with 118 

Markers, protection of 271 

! Marksman, percentage required for classification 131 

Materiel, value in examination for classification . 131 

Maxim gun, heavy type of gun 11 

Position exercises, illustrated 43 

Mechanics of the gun, thorough instruction required 13 

Mil, adopted as angular unit of measure 90 

Mil scale, use of in examination for classification 133 

Mounds, firing 262 

Night firing 129 

Night firing box description 130 

Noncommissioned officers: 

Assist officers in instruction 7 

Duties as scorers 284 

In charge of targets . 286 

Object of instruction 1 

Officers : 

Must undergo annual qualification test 7 

Other than machine-gun officers to receive instruction in 

machine-gun tactics 141 

Ordnance handbooks and manuals, use as textbooks in instruc- 
tion , 13 

Organizations not in regular service, course for !_ ;_ 301 



282 INDEX. 

Paragraph, 

Overhead fire .=, 124 

Peep sight, description of 20 

Blurring effect, how overcome 26 

Recommended in earlier stages of combat 26 

Use of, results in good scores 26 

Personnel, well trained, adequate course of instruction necessary. _ 4 
Physical training. Part I, Chapter II. 

Examples 15 

Essential to overcome premature fatigue 15 

Object of - 15 

Pit shed 26a 

Position exercises 38-44 

Benet-Mercie rifle . 39-41 

Lewis gun : I 40 

Maxim gun 43 

Vickers gun 42 

Illustrations of positions 39-41 

Men should not be kept too long in firing position 41 

Men required to take positions illustrated 44 

No hard and fast rules can be prescribed 38 

Speed not sought at expense of accuracy 41 

Post commander, duties of 9 

General supervision of machine-gun practice: 9 

Procures ground for machine-gun practice 9 

Recommends months of year most suitable for target practice 9 
Responsible for instruction of officers other than machine- 
gun officer in machine-gun tactics 141 

Sees that approved programs of instructions are carried out 9 

Preliminary instruction, period of . 4 

Adequate instruction necessary to have trained personnel 4 

Given as soon as man joins organization. '. 4 

Prismatic compass, training in use of 57 

Programs of instruction, post commander sees that approved are 

carried out : 9 

Qualification test: 

Coaching not allowed 282 

Individual field firing test . : 136 

Officers must take annual . 7 

Purpose of 282 

Rules and conditions for record practice 110 

Range finders, training in use of 54 

Range house 265 

Range officer, duties of, in solution of field firing problems 155-277 



INDEX. 284 

Paragraph. 

Eanges, target ' 253-277 

Classes of 253 

Class A 254-266 

Artificial butts 259 

Best ground for 257 

Danger signals 264 

Diagram showing shape and dimensions of area 255 

Direction of the range 256 

Distance from post 254 

Firing mounds 262 

Hills as butts 260 

Numbering of targets 261 

Pit shed 263 

Range house 265 

Rules for selection 254 

Scorer's tables 266 

Security necessary 255 

Size of range 258 

Class B, general remarks. 274 

Machine-gun ranges 267—273 

Area 267 

Distance from firing point to target 270 

Interval between targets 272 

Plan of range 269 

Protection of markers 271 

Selection of site 268 

Telephone service 273 

Range regulations 275-286 

Company target record to be kept in personal possession of 

commander until reports have been submitted 285 

Entries to be made in ink 285 

Director, personal representative of commanding officer, du- 
ties and powers 275 

Dress and equipment 281 

Field glasses, use of, to be encouraged 283 

Noncommissioned officer in charge of targets, duties 286 

Qualification test 282 

Coaching prohibited 282 

Purpose 282 

Range officer, duties of 277 

Must understand construction and manipulation of field 

targets 278 

Should be furnished with schedule of firing exercises 

one week in advance 278 



284 INDEX. 

Range regulations — Continued. Paragraph. 

Recorder, adjutant for director, duties of 278 

Scoring, how done 284 

Umpires, duties of 279 

Use of devices for determining force and direction of wind 280 

Recognition and designation of service targets 82 

Exercises in : 83 

Appearance of various forms of objects 84 

Searching a given area 86 

Should be progressive 88 

Teaching what to look for 83 

General remarks 82 

Good vision and power of perception necessary 82 

Scouts must be trained in 82 

Value in examination for classification 131, 134 

Recoil-operated guns, definition : 12 

Recorder of range practice 276 

Records and reports required 287-293 

Final classification 289 

Performance record for each gun 287 

Record of combac training 290 

Record of individual known distance record firing and quali- 
fication test 289 

Report of combat training 293 

Report of individual known distance practice 291 

Report of individual qualification test 292 

Records, firing: 

Department commander examines 10 

Of combat firing to be kept 188 

Reference point, use of, in target designation, 92 

Regimental commanders, duties of , 8 

Reports on efficiency of organization at end of target season. 8 
Responsible for instruction of officers other than machine- 
gun officers in machine-gun tactics 141 

Should be present in all exercises in which organization 

acts as a whole 8 

Supervisor and inspector of firing instruction 8 

Reloading, exercise in 51 

Dummy cartridges used 51 

Rate of fire dependent on rapidity with which piece is 

loaded 51 

Scale of machine-gun ordinates at 1,000 inches from muzzle of 

gun 100 

Scheme of instruction, arrangement 2 

Scorers' tables 266 

Scoring, how kept 284 

Scouts, must be trained in recognition and designation of tar- 
gets 82 



INDEX. 285 

Paragraph. 

Searching fire, definition of 47 

Mil unit of measurement in announcing amount of 47 

Practice in ____— -*• 

Searching with distribution, diagonal, exercise in _ 50 

Searching with distribution, exercise in 49 

Selected privates, assist as instructors 7 

Sharpshooters, percentage required for classification ,■_ lal 

Sighting, methods of 28-o7 

Exercises in — 

Heavy gun ^7 

Light gun 27 

Sighting and aiming drills. Part I, Chapter III : 

Line of sight, definition 23 

Methods of sighting machine gun not the same for different 

types of gun 27 

Normal sight, definition 25 

Peep sight, definition 26 

Point of aim, definition 26 

Purpose of 20 

Sighting bar, description of 21 

Target for sighting drill and its use 22 

To whom given 19 

Value of instruction in 18 

Sight setting and recognition of targets, value in examination 

for classification 131-134 

Sights, training in use of 56 

Speed in assuming firing positions not to be sought at expense 

of accuracy 41 

Supplementary practice season, reasons for 5 

Tangent sight, use in overhead fire 127 

Targets 239 

Description of 239-252 

Target B for obtaining sight setting 240 

Field targets 247-252 

Target E 247 

F _- 248 

G 249 

H : 250 

1 251 

K 252 

Known-distance targets 241-245 

MGA 242 

MGB 243 

MGC 244 

MGD 245 

Targets for field-firing exercises, appearance 150, 161 






286 INDEX. 

Paragraph. 

Target designation 89-93 

Definition, within company and platoon 89 

Designation of aiming point . 93 

Dividing target frontage into fractional parts 93 

Horizontal clock system 91 

Methods of 90 

Mil adopted as angular unit 90 

Mil system may be used for switching targets 93 

System of angular measurement important : 90 

Use of reference point 92 

Vertical clock system 91 

Target- practice months, post commander recommends most suit- 
able 9 

Telephone service, machine-gun ranges . 273 

Test, to determine sight setting for each barrel 111 

Test firing, ordered by department commander at annual inspec- 
tion 10 

Theory of fire___* 189-238 

Adjustment of fire 216 

Choice of means *. 217 

The battle sight, its uses__ 217 

Combined sights and searching fire, when used 225 

Conditions when justified and when not 228 

Employment of more than three elevations of doubt- 
ful value 227 

Table showing number of elevations to be used and 

depth of searching (in mils) required 226 

Fire for effect, definition 230 

Effect to be expected against various targets 231 

Advancing or retiring skirmish lines 235 

Aircraft 238 

Artillery ,__ 234 

Columns 236 

Infantry in trenches 233 

Prone skirmish lines 231-232 

Targets moving across the line of sight 237 

When employed 230 

Ranging fire : 219 

Choice of points to facilitate observation 224 

Continued ranging robs gun of element of sudden- 
ness 223 

Correction of sight as result of observation, how 

made ■. 224 

Elevation to employ for ranging 221 

First ranging strings must be long enough to in- 
sure observation 223 



INDEX. 28? 

Theory of fire — Continued. 

Adjustment of fire — Continued. --, , 
Ranging fire — Continued. Paragraph. 

Number of shots to be fired 222 

Simultaneous use of all guns by platoons, and 

single guns = 222" 

Summary when ranging may and may not be used_ 220 
Unnecessary against targets within battle sight 

range 220 

Visibility of target and impact first requisite 219 

Use of a single elevation, when used 218 

Table showing 75 per cent zone at various ranges 218 

Ballistic qualities of machine guns 189 

Same as Infantry rifle 189 

Limitations of machine guns 198-204 

Physical 198 

Compact cone demands precise adjustment 198 

Mobility readily destroyed by casualties 202 

More vulnerable than Infantry or Cavalry 200 

Not suited for continuous-fire fight_ 199 

Psychological 203 

Lacking in threat of personal encounter 203 

Powers of machine guns 191-197 

Physical 191 

Facility with which it can be moved from place 

to place 195 

Fire power compared with that of riflemen 192 

Mobility on the march 196 

Is that of Infantry or Cavalry with which it 

operates 195 

Movement of sheaf responsive to leader's will 193 

Particularly adapted to cover restricted areas 191 

Rate of fire not influenced to marked degree by 

variations in range 193 

Sheaf more compact than that of equal volume of 

rifle fire 191 

Size of sheaf depends on skill of gunner 191 

Vulnerability of personnel same as Infantry, but 

with very little loss of fire power 194 

Psychological, prestige as a deadly weapon 197 

Rates and volumes and their relations to effectiveness 205 

Amount of fire, definition 212 

Cyclic rate, definition 205 

Distribution ^factor 211 

Effectiveness of fire 213 



288 INDEX. 

Theory of fire— Con tinued. Paragraph. 

Rates and volumes and their relations to effectiveness — Con. 

Rate of fire 206 

Dependent on kind of fire used 206 

Differs for different types of gun 206 

Includes all pauses in firing 207 

Rate of impact, definition 209 

Volume of fire 208 

Volume of impact 210 

Summary of powers and limitations 204 

Training men: 

Company officers responsible for 7 

Position exercises to be followed 44 

Use of instruments 52 

Training organizations, officers responsible for 7-10 

Triangle of sighting ! 33 

Abnormal shapes, cause of 33 

Bright sights in strong sunlight 37 

Errors, causes and correction of 34 

Gauge for measuring :_: 33 

Shaded target and eye 37 

Umpire : 

Field-firing exercises, requirements, etc 172—187 

Reference tables 176 

Vickers gun — Heavy type gun 11 

Position exercises illustrated 42 



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V 



[C. M.-G. F. M. 1] 



MACHINE-GUN FIRING MANUAL. 

Changes 1 WAR DEPARTMENT, 

No. 1. J Washington, March 22, WIS. 

Paragraph 120, Provisional Machine-Gun Firing Manual, 
1917, is changed as follows: 

120. After the fourth line below the range table, on page 132, 
insert the following : 

The following range table gives the angles of departure (in 
mils) for the various ranges (in meters) for the Browning 
water-cooled machine gun, firing United States ammunition, 
caliber .30, model 1906. 

To obtain the true angle of elevation, the angle of jump 
must be subtracted from the angle of departure. For the 
Browning gun the jump is positive and is between 0.4 and 0.5 
mils. 

By obdee of the Seceetaey of Wab: 

PEYTON C. MARCH, 
Major General, Acting Chief of Staff. 
Official : 

h. p. mccain, 

The Adjutant General. 
5198C — 18 



[C. M.-G. F. M. 1] 



Range tabic, caliber .30 ammunition. 



Range in 
meters. 


Angle of 1 
departure 
in mils. 


Range in 
meters. 


Angle of 
departure 
in mils. 


Range in 
meters. 


Angle of 

departure 

in mils. 


100 


0.8 


1,150 


21.9 


2,200 


84.0 


125 


1.0 


1,175 


22.8 


2,225 


86.1 


150 


1.2 


1,200 


23.8 


2,250 


88.3 


175 


1.4 


1,225 


24.8 


2,275 


90.4 


200 


1.7 


1,250 


25.8 


2,300 


92.6 


225 


1.9 


1,275 


, 26.8 


2,325 


91.9 


250 


2.2 


1,300 


27.9 


2,350 


97.2 


275 


2.4 


1,325 


29.0 


2,375 


99.6 


300 


2.7 


1,350 


30.2 


2,400 


101.9 


325 


3.0 


1,375 


31.3 


2,425 


104.3 


350 


3.3 


1,400 


32.5 


2,450 


106.7 


375 


3.6 


1,425 


33.6 


2,475 


109.3 


400 


3.9 


1,450 


34.9 


2,500 


111.9 


425 


4.2 


1,475 


36.1 


2,525 


114.5 


450 


4.5 


1,500 


37.4 


2,550 


117.1 


475 


4.9 


1,525 


38.7 


2,575 


119.8 


500 


5.2 


1,550 


40.0 


2,600 


122. 5 


525 


5.6 


1,575 


41.4 


2,625 


125.2 


550 


6.0 


1,600 


42.7 


2,650 


128.0 


575 


6.4 


1,625 


44.1 


2,675 


130.9 


600 


6.9 


1,650 


45.6 


2'. 700 


133.9 


625 


7.3 


1,675 


47.0 


2,725 


136.8 


650 


7.7 


1,700 


48.5 


2,750 


139.8 


675 


8.2 


1,725 


49.9 


2,775 


142.7 


700 


8.8 


1,750 


51.5 


2,800 


145.8 


725 


9.3 


1,775 


53.0 


2,825 


149.0 


750 


9.9 


1.800 


54.6 


2,850 


152.3 


775 


10.4 


1,825 


56.3 


2,875 


155.8 


800 


11.0 


1,850 


57.9 


2,900 


159.3 


825 


11.6 


1,875 


59.6 


2,925 


162.8 


850 


12.3 


i;9oo 


61.3 


2,950 


166.5 


875 


12.9 


1.925 


63.0 


2,975 


170.4 


900 


13.6 


1,950 


64.7 


3,000 


174.2 


925 


14.3 


1,975 


66.4 


3,025 


178.1 


950 


15.1 


2,000 


68.2 


3,050 


182.2 


975 


15.8 


2,025 


70.1 


3,075 


186.3 


1,000 


16.6 


2,050 


72.0 


3,100 


190.5 


1,025 


17.4 


2,075 


73.9 


3,125 


194.8 


1,050 


18.2 


2,100 


75.9 


3,150 


199.0 


1,075 


19.1 


2,125 


77.9 


3,175 


203.5 


1,100 


20.0 


2,150 


79.9 


3,200 


208.0 


1,125 


20.9 


2,175 


82.0 







(C. M. G. F. M., No. 1, Mar. 22, 1918.) 
[413.68, A. G. 0.3 



[C. M. G. F. M. 2.] 



MACHINE-GUN FIRING MANUAL. 

Changes \ WAR DEPARTMENT, 

No. 2. J Washington, April 25, 1918. 

Paragraphs 126 and 127, Provisional Machine-Gun Firing Man- 
ual, 1917, are changed as follows : 

126. To determine this in any concrete case, the range table 
given on page .132 is used in conjunction with the following: 

Table of safety angles. 




(C. M. G. F. M. No. 2. Apr. 25, 1918.) 
[353.4, A. G. O.] 

61607°— 18 



[C. M. G. F. M. 2.] 



127. In direct overhead lire, the gun is placed in position, 
the sight set at the correct elevation, aim taken at the target, 
and the gun then clamped in position. Without changing the 
elevation of the piece, the sight is then set at the " corresponding 
range " to the safety angle as per the above table. With the sight 
thus set, the point of aim is noted, and, if this point of aim is 
found to be at or above the feet of the troops, then overhead fire 
is safe. If the point of aim is found to fall below the feet of 
the troops, then overhead fire is unsafe. 

If for any reason it is desired to solve the problem of troop 
safety without putting the gun in position, it can be done thus : 
Measure the vertical angle between troops and target. Add this 
angle to the angle of departure (see range table on page 132) 
corresponding to the range (angle site not considered) to the 
target. If the sum of these two angles is equal to or greater than 
the safety angle corresponding to the distance to the troops, 
then overhead fire is safe. If this sum is less than the safety 
angle, then overhead fire is unsafe. 

In indirect overhead fire, find the angle of departure, in- 
cluding angle of site, required to hit the target and find the angle 
of site to the troops. If the algebraic difference between these 
two angles equals or exceeds the safety angle corresponding to the 
distance to the troops, then overhead fire is safe. If this dif- 
ference is less than the safety angle, then overhead fire is unsafe. 
(O. M. G. F. M. No. 2, Apr. 25, 1918.) 
[353.4, A. G. O.] 

By order of the Secretary of War : 

PEYTON C. MARCH, 
Major General, Acting Chief of Staff. 

Official : 

H. P. McCAIN, 

The Adjutant General. 



WASHINGTON : GOVERNMENT PRINTING OFFICE : 1918 



